Since it's been so long, I'd call a dermatologist. I have lots of mystery skin ailments, but have never had anything that sounded like yours. Are the bumps itchy or filled with pus? I don't think you can get acne on your legs. It's probably some type of systemic thing imo. Here are some suggestions (there all things I do):
If you're using anything in your bath, stop and just go with water, try a hypoallergenic soap. If you bathe your baby in the same tub you use, don't use any special soaps or washes (same goes for DH if he uses the same bath tub).
I can't use perfume of any kind on my skin including deodorant, perfumes, soaps, lotions etc. They all have to be hypo allergenic or I get majorly itchy bumps. I spray my perfume on my clothing and then put it on and so far that hasn't caused a reaction. If I forget and spray perfume on my skin, I get red bumps where I sprayed it.
Also-dryer sheets-they caused my legs to get so red and bumpy, I thought I had scabes. I told DH I was allergic to them, but he didn't believe me and was sneaking them in the dryer when he did laundry. I nearly killed him. I was miserable for a month until I found out what he was doing. That and he was using fabric softener too!! Double whammy for me.
Good luck and I hope you get some relief soon. If they're itchy, there are some oatmeal things you can get at the store to put in your bath to stop the itching.