I had Cantharidin done to my foot a previous time and it turned black and caught an infection very fast, I had it done on three sites yesterday and the same one is turning black and burns but the wart is on top this time , the other sites aren’t dark or anything and it said the blister should form after 24 -48 hours but it hasn’t been 24 hours and there’s a blister already? I don’t really know how it is supposed to feel or look since mine infected last time , could you help me ?