I don’t know if you’ve tried this but it may help if you haven’t or you could at least try if you haven’t already.
I had bad break outs of acne and blackheads for a long period of time that I couldn’t get rid of. It was awful and painful. Tried everything, like you did, including antibiotics for acne.
There was one point where it got particularly bad, but this time was different as the breakout didn’t just affect my face or chest area, it affected my face, chest, back, ears and came on very sudden.
Somebody suggested at that point that it may not just be acne but a possible allergic reaction. They suggested strong allergy medication, antihistamines.
I was dubious but tried it anyway. My skin cleared up very quickly. The more I took them, the better it got.
The theory is, maybe I was eating something or drinking something or exposed to something I wasn’t aware of and that was part of the reaction.
It’s worth noting, I saw dermatologists and many doctors as well as many tests and it’s not until I worked it out about the allergy reaction that it occurred to them too and they agreed at that point.
Prior to that, it was just assumed acne as I hadn’t exhibited any major symptoms of allergy Til my really bad reaction. They agree now though.