My Son Had A Fever Of 101.3 Last Monday So

My son had a fever of 101.3 last Monday so my husband took him to walk in and they said he had hand and foot virus..... Well he got this sore that looked like I pimple on his arm that he was scrating I guess and picking at it well..... Now its super read around it and keeps getting big and puss and blood is coming out of it I keep cleaning it and putting a band aid on it at night but then it get super big again so I keep repeating what I am doing... Wondering if I should take him to walk in or wait till our appointment on Friday....