Your boyfriend is having sebaceous cyst... It is also called epithelioid cyst
After squeezing the cheesy material cyst becomes empty, but cyst remain there with hole.
The cyst might be removed by excision under local anaesthesia .
It is very simple surgical procedure done in OPD.
So, take your friend to sugeon or dermatologist
.. for the treatment.
He will be alright ..ok
I hope you got my answer.
Dr. Ilyas Patel MD