I sympathize; When I was a kid, I used to get horrific sore spots on my fingers sometimes while crocheting. Usually mine weren't blisters; they were more like callouses. I don't know of any commercially available appliance that could prevent this, but when I was a kid I used to wrap a band-aid around the affected spot, and that helped a bit. I am not sure that would help you; it might but I am not sure because your issue sounds a bit different than mine.
First of all, I'd definitely recommend allowing your hands to heal completely before you crochet again.
Here are some suggestions you can try.
If you notice this happening in spots where your fingers are coming into contact with your yarn, try using a different yarn and see if that helps.
It is possible that you could be allergic to the fiber, or one of the fibers, in the yarn that you are using.
The problem might not be caused by an allergy; it's also possible that your blisters could be caused by excessive abrasion. In my case, I noticed that my sore spots were happening when I would crochet with abrasive yarn for long periods of time. In general, you might wish to avoid crocheting with abrasive yarns, or at least using them in moderation. Try switching to a softer yarn and see if that helps.
In my case, the sore spots were happening on the hand that holds the yarn. If your blisters are happening on the other hand, the hand that holds the hook, you could try switching grips to see if that helps. If you're a "pencil gripper," try the "knife grip," and vice versa. You could also try using a different crochet hook.
Depending on your situation, the following links might or might not be relevant:
If you think an allergy could be causing or contributing to the situation, Dr. Daniel More's allergies site could be a good resource for you:
Also, feel free to post your question on our crochet forum if you'd like to get input from other experienced crocheters. I am sure there are plenty of others out there who have experienced the same thing, and might be able to give you some additional insights.
Thanks for getting in touch! I appreciate your interest, and I hope this information is helpful.