Welcome to the board. We all understand what you are going through as we have all been there. I am relatively new to this too and also have concerns about others being able to deal with my girl if I want to go away for a few days. My cat tends to be fairly laid back and is OK with strangers petting her but is not one of those cats who greets everyone who visits. I too wonder if her reaction to testing and injections will be different with a stranger when I am not here. I'll share my thoughts on dealing with the vacation dilemma but first I have some questions and thoughts.
What kind of insulin are you giving Chloe? You indicated 1ml twice daily. I assume you meant 1 unit twice daily.
Am I correct to assume that her glucose level of 400 is the # the diagnosis was based on and not a reading after insulin was started?
Was Chloe showing any signs of diabetes before you noticed the swelling in her face...things like excessive drinking, excessive peeing, weight loss, extreme hunger? Usually some or all of these symptoms become quite evident in diabetic cats.
The reason I ask is that a cat's glucose levels can be elevated as a result of an infection. Cats often tend to have elevated glucose levels while at the vet's due to stress. Some cats react more than others and their glucose levels can be elevated by 100 points or more by stress alone. Chloe obviously was highly stressed at the vet. Taking the abscess, the surgery and the likelihood of stress glucose elevation into consideration, it strikes me that Chloe's normal glucose levels may not be nearly as high as it appeared to be while at the vet. Only by testing at home in a stress free environment once Chloe has fully recovered from the surgery and the infection, will you get a true picture of just what her glucose levels are. If she didn't have any prior symptoms of diabetes, I am wondering if Chloe is truly diabetic and even if she is, whether she might be one of those kitties who can be controlled on diet alone. If either were the case, you would not have to be concerned about someone else doing injections in your absence.
If you are not already home testing Chloe's glucose levels, I would strongly recommend you do so. It seems likely it's the only way you are going to get accurate readings for Chloe when she needs to be sedated at the vet. You indicated you have a follow up appt. with your vet in a couple of weeks. As Chloe recovers from her surgery and the infection, she might need less insulin or even none at all (fingers crossed!). Any numbers taken at the vet's office are likely to give you higher than normal values and could cause your vet to overestimate her insulin requirement. You don't want Chloe getting too much insulin while you are away as I presume she will be alone most of the time. Too much insulin could lead to hypoglycemia which can be life threatening if not caught and treated quickly. For that reason, getting accurate glucose readings without any stress influence is vitally important.
You obviously love Chloe and want her to be healthy and safe. It is not my intention to increase your concerns but rather to keep Chloe safe and I truly feel the only way to do so is to start home testing her glucose. It's really simple to do and as with the injections, most cats don't have any issue with it at all. Some of our cats actually come to get us when they are due to be tested!

There are wonderful people on this board with tons of experience willing to help you get started, answer any questions you might have and provide tips and tricks to make dealing with all of this easier.
Most folks on this board use human glucometers and you can often get one for free when you buy the glucose test strips for the meter. There are lots of reference materials available here too. I'm sure one of the "experts" will be along to chime in and offer more suggestions. As I mentioned I am relatively new to this adventure myself and still learning but the circumstance of Chloe's diagnosis make me truly wonder if she is diabetic or just had an excessive glucose elevation due to her illness and vet visit.
Now back to your question in case my hopes of Chloe possibly not needing injections going forward doesn't pan out, did you have someone lined up to look after Chloe in your absence before she was diagnosed? Are they willing to do the shots for you? If so, you could ask them to come over a couple of times before you leave to learn how to test her and do her injection and see how your cat reacts. I plan to do some dry runs with some friends I have lined up for my girl. After they are comfortable with the process with me there, I will leave the house, have the friend (sitter) go in alone and do the testing and shot with me closeby ooutside to help if needed.
If you are know your neighbours well enough, maybe one of them would be willing to do the shots. You could also see if any of the vet techs at the vet clinic would be willing to drop by to look after Chloe. They have lots of experience dealing with moody cats! If you are in an urban area, there may be some profession pet sitters who would do this but that can get expensive. You might even be able to find someone on this board in your area who is willing to help you out. If your Mom can do the shots, Chloe has already accepted someone different so she may not be as much of a problem as you anticipate. I agree that boarding should be the last resort especially with a cat that needs to be sedated for a vet visit. Cats get attached to their environment as much as their people and are much happier and usually more co-operative in their own home.
Sorry for the novelette.

I really hope that my intuition plays out here and you don't have to worry about testing and shots for Chloe while you are away. Right now though I think the priority is to find out what Chloe's glucose levels are when she is lounging around in the house without a care in the world other than when her next meal or cuddles are going to be dished out!
