help!!!

Someone help me 😭! My little boy has just came back from being on holiday, he was crawling around the pool area and ended up with a little scab, but when we got back home, the more he crawled the worse it's got! Before this it was just a small little scab, all healed and the next day he ended up with a blister and it burst at nursery. I took him to a pharmacy which they told me to put savalon and cover it up when he is crawling and just keep it open when he's sleeping! Everyday it seems to be getting worse and bigger. This has started from Monday, nearly a week ago. does anyone know what else I could do??