My 2 1/2 year old daughter had a bowel movement in the bathtub and was sitting in it for a few minutes afterward. She may have gotten some of the bath tub water in her mouth. This morning, she woke up and there was a large green and red blister on the side of her thumb. I burned a safety pin tip and punctured it. It sprayed pus and a lot of blood. It refilled right away with blood. I put neosporin on it and a bandaid. Its still puffy, but not as large and round. Its dark red, purplish, and black colored. I gave her some childrens acetaminophen, too. She has no fever and no swollen nymph nodes.