My son had this and gave it to all of us. It’s called Molluscum contagiosum and there is no treatment. It will go away on it’s own, but may take awhile. You need to completely avoid touching the area and if you do, wash your hands with soap. Cover with a bandaid if in a spot where it will rub against unaffected areas.

Babies are known for weird skin things, most are harmless, nothing to worry about and usually clear to by themselves pretty quick