How to deal with extreme self criticism and anger ?

So, I've been living for quite years with bipolar but I noticed that even outside episodes, I just criticize myself way too much about anything I've done. Something happens, then that's my issue, I blame myself very harshly. Then to stop my anger towards myself or the criticism, I mostly hit my head.

So I want to know how can deal with this, it becomes very embarrassing, sometimes things are said in my head and I react such way publicly without noticing (starting to hit my head again), then I become more embarrassed after. Sometimes I just start screaming at the voices that blame me, then I scare people around.

I don't like being looked at that way honestly.

What's the issue ? Is this related to bipolar ? I was like this when I was kid too, I used to bite myself though.

If anyone who has similar experience I would really appreciate it honestly. Thank you.