Hardness under incision site?

Hi, I had arthroscopic surgery 15 days ago. The stitches came out 8 days ago (probably sooner than they should have, because 2 of the 3 incisions split open almost immediately afterward). Anyway, one of them has this strange, very firm spot next to/under...

it. I won't say lump, because it's really beneath the skin, not making the skin stick up any- you can just feel it when it gets washed and recovered, etc. It's probably an area of about 1 square inch that's really firm like this- like there's something hard that you can't see there.

The question is: what is this? Is it scar tissue or something I don't really have to be concerned about, or could it be something else? Should I go to the doctor early (my next follow-up isn't for another week and a half) or just let it go?

Thanks!

Maybe it's dissolveable stitches that are sticking out a bit?

In any case if it doesn't hurt, phone your doctor to ask if you should be worried, otherwise schedule your appointment for earlier.