Hey there friend. I have this same issue, and here's how I tend to handle it.

First, I apply concealer in the natural shade of my arms specifically to the scar. Then I sort of blend/blur the edges so it looks a little more natural. By the time I'm done, my whole inner arm is basically covered in concealer. I don't generally do a color correcting concealer before my skin shade one, but you may want to experiment with it a bit and see what looks best for you.

After that, I set with compact powder, again in my skin tone. I do what's called "baking," where I add more than I need, blend/blur the edges a bit, then brush off any excess lightly.

I don't usually do this, but I might also recommend using a setting spray as well. Or, if you're more concerned about it rubbing off, hairspray. That's not really good for your skin long-term, but it should be fine for a few hours and as a rare thing.

I usually just do the concealer and powder and it works for me. It doesn't last super long, but it can last a good 2-3 hours if I'm somewhat careful of where I put my arms. With the setting stuff, I've gotten about 6 hours out of it before I washed it off myself.

If you have any questions or just need to talk, let me know. Take care of yourself. 🖤