Ah, that rash! I have had this on on off since October. Thought it was from bug bites as that is how it started. Nope, it is my normal seasonal allergies increasing. Not PG or VG, I didn't even know about e-cigs, much less ingredients in October. It was so bad that Patient First was giving me double antibiotics and antibiotic shots. They were afraid it could be MRSA! However, I asked them to test for that and they would not. 3 weeks ago they suggested I go to a dermatologist as they had no answers and antibiotics were not working. (This rash got bad, itchy, oozing, I will not go into it, but it was on my leg from a bug bite, next my face, then my arm.) Dermatologist immediately says it is an allergy. Are you allergic to poison ivy, I said I guess, but have not been around any. Do you have "hayfever", yes is the answer. Steroid cream is clearing just as your hydrocortizone is. I now need to see an allergy specialist, since this is just from pollen, but don't want to go through the process. (And, yes, every time I go outside for more than 1 block, there is a new tiny patch of the beginning of it again. Danged pollen!)
Take the advise above and go to a doctor when you get a rash for more than a week. I looked like a Klingon for a few weeks before my bosses told me to get to the doctor, sad but true. Don't let it get that bad, it can leave deep scars. (Money worries can blow, just go get some medical help. Deep scar on leg and on face, right in between my eyes b/c I did not get started with a doctor earlier.)