pimples on head

I was wondering if anyone had suggestions to relieve or treat blind pimples that have started appearing on my head.  They come up very quickly, are about the size of a 5 or 10 cent piece, inflamed red, no white head and extremely painful. I have had to take painkillers to try and reduce the throbbing and have also placed heat bags on them (which does help a little).  I read that chemo can cause acne so I am presuming that is what these huge welts are. I am 3/4 through my chemo and these have only appeared in the last week. Any suggestions will be gratefully received.