Hello! What a tough predicament to be in!! After all that time growing and caring for them, you've got to leave for a month during a critical time! Before I continue, I will say that I believe the dry and cure stages are just as important (or maybe even more!) as the veg and flower stages. So much happens during the dry and the cure and you can taste/feel when those stages weren't done properly.
At the end of the day, if you have to dry them, jar them, and leave for a month, you've gotta do what you've gotta do. However, don't be surprised if you come back to a moldy, unusable bunch of jars. The reason for this is that even after drying to what you think is appropriate (about 58% in jars for a couple hours or longer) sometimes they're actually more moist than you think. When you're opening them, daily, smelling them, shaking them gently to make sure they're not stuck to each other so that there's airflow, etc., you can keep an eye on the trend of what the moisture is doing. It's not unusual that after a couple few days of curing that jars with bigger buds end up getting above the high end of ideal (over 65%) and you have to either leave the jars open for a few hours or sometimes even spread them out in a foil pan or something of that nature to allow them a little more drying time. If you're not looking at them for a month, it's very possible that you'll miss that opportunity resulting in bacteria, mold, fungus, etc which would make your buds unsafe to consume.
As Bluey said, you could overdry them and then try to 'rehydrate' them. Just know that there's a reason that's not the way it's done...it will result in subpar flavor and experience and could still result in bacteria, etc.
There are a lot of things that happen during the cure (other than just making you wait to try your tasty buds!) that contribute to the final taste and experience. Different compounds break down like chlorophyll, the moisture distributes itself more evenly, etc. To do these processes, the jars need to be opened at least daily for at least the first two weeks.
So, best case scenario, you over-dry them then rehydrate them and you have mediocre buds. Worst case, you come home to jars of unusable and dangerous buds. I don't envy your position one little bit but I certainly wish you the best of luck!!
