Cradle cap?

LO is 5 months old and has this rough yellowish white scales on her scalp. It doesn't look like the greasy yellowish crade cap on her hair roots which is mostly gone now. It's been there for more than a week and now I feel it is getting rougher and spreading. I have been applying olive oil on her scalp.

Should I take her to doctor? I am worried it might be some infection. Any tips to get rid of this is appreciated.

Update: Thank you so much everyone for the tips!