I.G.
You do need to see the pediatrician. It could be anything from a fungal infection like ringworm to psoriasis. Just using a conditioner or OTC stuff can make it worse.
Treating it like cradle cap can make it worse as well, if it isn't cradle cap and by trying to remove it you break the skin, you may end up with a bacterial infection on top of whatever it is.
Good luck!