SuZir -- Wow. That's a whole lot to consider. A whole lot. Thanks for sharing more in-depth. Didn't mean to pry, just wanted to understand better.
Hmmm.... Capsaicin for self-harm. Honestly, I've never heard that before. Unusual. He ever do any big damage with it that required significant medical attention? Pins under nails is also unusual (although I have heard of that, at least). I did know someone who carved in his arm with glass. But capsaicin is a new one for me to hear.
Bipolar is always a valid consideration when things go into extremes or oddities. Our son is bipolar. "Persona" may differ in denotation and connotation. I don't know. Something to research (in terms of DSM, etc) or consult a professional about.
Again, that's a whole lot to consider. And he's right at the age where those things may bloom wildly. I send you best wishes for more clarity, understanding and options. It's quite a maze trying to figure it all out sometimes!
Wishing you all the best, SuZir!