Does anyone know what this could be?

That's what I thought too. They aren't bumps though

It looks like ring worm

My sister said ring worm too. Idk how she would get that though

Ringworm.

Tea tree oil or anti fungal cream.

Ring worms. My niece had them n now my daughter got them but on her butt. Try lotrimin from Walgreens or CVS it works and he might need antibiotics. The blister really bad.

My daughter had marks that looked like that and it turned out to be eczema.

Thank y'all