E.T.
Could be molluscum. Our daughter has been battling it for 3-4 years, mainly on her face. Hers would start out looking like a red bump, start to look more like a pimple, form a core like a wart, and then form a head that would dry up and fall off. It would form a head 2-3 times before going away. It would take 6+ months for each one to disappear. They normally didn't bother her except for one in the corner of her eye that bothered her when she rubbed her eyes, and one on her cheek that got infected after we were at a water park.
If it is molluscum there isn't much you can do. Let the virus run its course, freeze it, or scrape it. We tried freezing one of her first ones, but she was only 2 and it was close to her eye so the doc didn't want to do too much with it. Freezing didn't work. The one that got infected we did treat with an oral antibiotic. Then a dermatologist scraped it and froze it. The core was huge and the doc thought it might have been the "mother". Once it was gone it cleared up off her face. But at her 7 year check up last week the doc thought some "pimples" on her butt were actually molluscum, too.
Supposedly it is highly contagious, but no one else in our family has had it, no one else at daycare or school ever got it. I would take her in and see what the doc says.
http://www.mayoclinic.org/diseases-conditions/molluscum-c...