AITA for not wearing long sleeves? tw // self harm

recently i (20nb) had a particularly bad week and relapsed. i dont do anything that leads to any major injury but it does leave visible marks on my wrists.

after a few days i kind of forgot about them? i dont care about people seeing them all that much (obviously i do tend to wear longer sleeves to hide them, but theyre a part of me just like any other temporary scar. i dont bring them up ever i just let them exist. all this to say if i wear short sleeves its not the end of the world for me) and im in the middle of art school finals right now so hiding my scars is not my priority lol

recently i went out with my family (my mom [49f], my sister [16f] and my brother [14m] if it matters) to get haircuts. the haircuts are by a family friend (63m), and he is well aware of my mental health issues. once i got in the car, i realized that i put on a short sleeved shirt today. we werent exactly gonna go out and do stuff other than haircuts and burger king, so i thought it would be fine. the scars, at this point, have faded to nothing more than faint red lines and are barely noticeable.

long story short, my mom saw them and dragged me out to the car after our haircuts were done. once we got to the car she laid it in on me. she yelled at me, asking me things like "how dare you do that to yourself again", "how dare you show them off to [haircut guy]", "why did you think that wearing short sleeves was even remotely a good idea?". i tried to explain it was an accident, but she pointed to the scars and asked me how "that" was an accident.

i will admit that i didnt have a good answer for that and stayed silent. my mom didnt like that and accused me of everything from earlier again, and then marched inside for my siblings, saying she wasnt done with me.

im now back at my dorms after a very silent car ride. ive already texted my dad (49m) about the situation, who is backing me up, so hopefully the argument will resolve here, but judging from my moms visceral reaction, i feel like an asshole. the intent wasnt to "show them off", but i should have worn longer sleeves to hide them and make sure that i didnt freak out my mom. shes autistic and cant control her emotions very well (she hasnt gotten therapy for it) and she might have been stressed since ive had issues with sh for 7 years now and i was 4 months clean before i relapsed (and she mightve thought that i broke free of the habit).

... though as far as im aware, neither my mom nor my haircutter have had issues with sh in the past, and my haircutter didnt notice my scars.

sorry for long post; aita?

What are these acronyms?