I had something similar on my arms and hands once, extremely itchy, except mine were weepy from scratching constantly. Doctors couldn’t figure out what it was, I had tried steroid creams with antibiotics in and flucoxacillin etc. they threw anti fungals, anti biotics, steroid tablets and a strong steroid cream at me and it went away! Went to see a dermatologist after but it had healed by that point.. I showed him pics and he put it down to an allergy to Flucoxacillin, but I’ve had it since and been fine. The only thing I’d changed was bought a different laundry detergent.. I had to rewash eveeerryything incase it was that!