hello...thanks for consultation with HCM:) first of all it feels great that you guys are taking great care of your elderly mother. As the skin goes fragile, minor scratches,injury,some chemical exposure might cause blisters. Usually, it is best to leave blisters alone. Because blisters protect the underlying skin, breaking blisters open can increase the chance of infection. Protect blisters with a bandage and cover them until they heal on their own.you can apply caladryl lotion over affected area thrice daily, also would care is important. But if it becomes very painful blisters, or blisters accompanied by other symptoms such as fever and malaise (a generally sick feeling). Also call on a if a blister develops signs of infection, such as increasing redness, red streaks in nearby skin, oozing blood or pus, increased pain or swelling of the surrounding skin. Also in elderly individuals there s a chance for Pemphigoid and pemphigus that needs typically chronic (long-lasting) and require long-term therapy. thanks n wish your mother a long & healthy life:)