Rash on the back of babies neck. What is it!?

Hi all! I am a first time mom to my 10 week old boy. He was 4 weeks premature. I know that on his face he has “salmon patches” but he’s been getting a rash on the back of his neck/head. It’s been getting a tiny bit worse. I have been reading up on rashes and some have said it’s a stork bite but I don’t think that’s it.

Have any of you experienced this kind of a rash and what could it be? It looks like some skin is also peeling in the rash. Any suggestions or help is appreciated!