I have developed red bumps on my lower back, that look a lot like spider bites. I ve gotten them before, but usually they go away fairly quickly. I exercise 6 days a week, and this last week in particular was very intense. I ve gotten these blister like bumps before when exercising and sweating A LOT, but this time it s spreading and more intense... what do I do? What is it???? They are red, some larger than others, and itchy at times.