is it true having anal gives you a straight lined scar above your anus?

My boyfriend was talking to me about how his ex had a scar like that and he didnt know where it was from, but that she'd mentioned trying anal before, then after they broke off his friend told him you get such a scar from anal.

A few years back I was anally raped, and I've noticed the scar on myself before but didnt connect it to that, I genuinely didn't know how it got there. My boyfriend hasn't seen it yet and how exactly do I explain without sounding like a liar.