There's a lot of different ways this could go with clients.

On one hand, it might be encouraging, and give a client hope for recovery, or let a client know that you had "been there", too. On the other, it might make a client scared about your stability, or worse, trigger them into wanting to SI or make them feel hopeless that they can't recover. I think it's also really different to say "I used to SI" and have them actually see the scars.

Ultimately, though, it boils down to the individual clients. It might be an interesting experiment to let them see your scars and see which ones bring it up and what they say.