I have painful burning rashes in my back, legs and arm. With photo

I have painful burning rashes in my lower back, in my thigh and arms. I don't know what it is. First I feel burning sensation in certain areas of my skin but when I looked at it, I couldn't see anything. There's nothing there. The next day these rashes started to come out in those painful areas, as seen in the photo. It is not itchy but it is painful when you touch, like burns. I have these rashes now and I have other rashes growing in the other parts of my body. The old ones are starting to have blisters. I did not take any medication. Please help.