Hi Pregpan. Um, I just had a thought. Are your pimples going away (individually) after a few days? I am occasionally prone to an unusual form of acne where the pimples come up all inflamed but never really develop a head and then they just hang on and on. It looks a bit like an allergic sort of rash. Usually it is concentrated around one small area on my face. When this happens, I get a script for a topical antibiotic (eryacne I think it's called) and they go away after a fews weeks with that.
I use Eryacne also. Your GP can give you a prescription for it, it is safe to use with pregnancy as it helps by killing the bacteria on your skin. Most acne medications very your hormones so obviously those are a no no while you are pregnant.
I have PCOS so have always have had problems with acne, mainly on my back but also on my face. I had cystic acne on my lower back until I got pregnant and thankfully that cleared up altogether, I now get the odd spot on my face and upper back and find the Eryacne helps, i use it mainly on my back though as it can be a bit drying on my face (although i do use it on my forhead as that can get a bit oily so the drying helps!)