Welcome to HealthcareMagic forum,
If your dermatologist
is sure that it is milia ,then you do need a radiotherapy for that.We see milia almost every day and do extract them .The extraction of milia just requires a 26G needle and an comedome extracter.It come out easily with out any residual marks.And it is not costly atall.
So I would advise you to take a second opinion
too or ask your dermatologist for an extraction only.