Hi there. Your history & clinical description am afraid do not tell us where exactly these red spots are located. Assuming you link it to sexual activity, they are on your genitalia. Also you state you are with a long term partner & both checked out negative for any STD
. There does not seem to be a link tween the boil & the other rash
. It is possible you developed an 'allergy
to the fluclox antibiotic you consumed. Please take an antihistamine & stop the anbtibiotic. If it still persists, you need to visit your nearest dermatologist
. Good lUck & CHeers!