Just knowing that it was a thing and a symptom of ADHD helped me a lot. I was able to not take things as personally and saw it from the perspective of my ADHD disregulation. It still feels horrible but after the initial feelings, I can let it go and move on.

This video helped me a lot when I was really struggling with RSD: https://youtu.be/jM3azhiOy5E In practice, it was a lot of mindfulness; I needed to pay attention to how I felt and what made me feel that way. In one notable instance, I learned that a fair amount of my RSD at the time came from interacting with one person, and I had to work on ways to get around it. Other times, I had to pay attention to when I was starting to feel... well, RSD, i guess... and excuse myself from the situation, let myself feel things while reminding myself it was RSD, it was temporary, and I'd feel better soon, and then I'd eventually go back and communicate the issue to my (very concerned) friends.