Seems if you have the strength and wherewithal to die in such manner, for a cause, than you would have that same strength to fight and conquer whatever your demons are.
Your cause would be greater served by your presence and will to stand up continuessly, rather than a one and done statement that will be forgotten within the time it takes to do the investigation that would come from the powers that be, and the excuses those those same powers would broadcast to show you where deficient of mind to pull focus from them and the fray.
Self immolation could definitely be used as a political statement: goes something like this......
I do this because ------- (fill in the blank).
Strike the match, suffer for God knows how long, die.
Powers investigate, statement released: ------(insert name here)
Had a long history of mental health issues, evidence shows ------ had been on a suicide forum before the incident seeking advice on suicide.
We regret that this unfortunate incident has occurred and wish the family peace at this time. End statement.
You have suffered, your family is still suffering, your friends and acquaintances are still suffering, you have been publicly outed as some kind of headcase, this is what everyone in your circle is left with.
Your cause continues to operate as before the only thing that has changed is the pain and grief left to those in your circle.
And you suffered hideously again why ?
What good has come from your actions ?
This is my opinion of course.
I hope you find peace, think carefully about the collateral damage to others that you care about and leave behind beyond your cause.
Stopping your personal pain by CTB is one thing, using self immolation as a means seems more like a cry for help that can't be answered ever, you are now dead.
Once again, my opinion, no judgement, hope you find your way.
Personally I want to be at peace in those final moments, not make the pain worse and suffer more.