My 7 month old puppy was neutered about 3 weeks ago. The wound has healed, however, there is some redness now. There is a blister-like wound right beside the area (but not over it) and two other red spots on the area. He is in absolutely no pain, even when i touch the area. I don't know how to clean it or if i should. should i be terribly worried or could it be from getting dirty after healing, licking, etc.?