Is it obligatory to repeat the prayer if very few drops of water, resulting from scratching a skin allergy without noticing it, get on the body or clothing?

Water that comes out due to skin itching is pardoned, and there is no need to wash it from clothes or the body if it is very little, and prayer is valid with its presence. So, what flows from wounds, sores, or the like is pardoned due to the difficulty of guarding against it if it flows by itself. The criterion for determining whether an impurity is little or much is custom, and whatever is doubted whether it is little or much is judged to be little until its muchness is certain.