Hi Melissa, I know what your experiencing, I have been through that. I can be your detergent and the moisture of the lotion will actually make it worse, it did in my case. You need to get a natural/organic lotion. If you're like me, I love wearing Victoria Secret lotions/perfumes but sometimes I can't. I have to use that organic stuff. I find cool things at Bath/Body Works or Trade Joes (Natual Food Store). The detergent I use is Tide. It's the one that doesn't have anything in it, I also use to use Dreft for babies/toddlers. It's expensive, but it helps also. The other thing that If found that worked when I had that rash was a tanning salon. I know it's strange but for whatever reason it helped. I went to a tanning salon to get ready for a vacation that I was going on and decided to tan. When my tanning sessions were over, the rash was almost gone. It was so wierd. I put tanning lotion all over my body except on the areas where I had the rash. You might try it.
*Hugs, Thoughts, and Prayers*
*Shel in New Mexico, USA*