Can you ride a horse with rain rot? Also do I need to put extra pads if I can?

Well my horse (well not "my horse" since I don't really own her but I'm the closest thing to an owner she has) has rain rot on her back. I can only visit her on weekends and there is a camp coming up in a few weeks (I always ride her at the camps) To get to my point: 1) Can I ride her with rain rot on her back? Do I need extra blankets if so? 2) Can I ride if there is no more of the mite just bald patches? Do I need extra blankets? 3) How fast does it take for the mite to be killed? How long for the bald patches to regrow hair? I want her to get better and to be able to ride my baby and not to hurt her worse than she is. Many of the horses where she lives have rain rot. Thank you for responding and I hope these answers can help me and future people.