I have experience with this unfortunately

Go and see a Dr and get a scraping done to be sure. You will need to not put anything on it for 7 days before hand so that it is an uncontaminated sample. I know it will be hard mentally but if it turns out to be tinea (ringworm is tinea) then you will know exactly how to treat it.

If it's really bad and the cream doesn't help (you need to use the cream for 2 weeks after they disappear, not just for 2 weeks. I made the same mistake and they came back with more and they were more resistant) or gets in the scalp then there are oral meds you can take. The course is really long though depending on their age/weight. I had to see a paediatric dermatologist to get these though as my Dr didn't know anything about the meds and wouldn't prescribe them.

PM me if you need to know any specifics