Thanks for posting your query. I will be glad to be of assistance.
I will try my best to answer all your queries till you get a satisfactory answer.
From your description it seems to be either allergic contact dermatitis
or it could be a case of vesiculobullous disease
like pemphigus vulgaris
In order to understand the concern better I would like to ask a few queries:-
1. Are these blisters confined to the leg?
2. How big are they, how many, are they tense blisters?
3. Do they contain water?
4. Are they closely grouped?
5. is there any itching?
Please let me know about the queries I have asked.