What Is The Treatment For Small Bumps In The Ear?

My 4 and a half month old baby has what looks like little bumps/pimples on his neck by his ears. It doesn't seem to bother him. Wasn't sure if it was anything I should have checked out, or just keep an eye on it. Thought maybe it could be irritation from his bib or shirt neckline or if it could be from allergies or something serious. Thank you.