Is it just healing?

So what's up with this? I put a harness on my dog because it's easy to control her with and I usually leave it on all day because it's easier than having it on and off every time I have to take her out. I haven't been using her harness for about a week now though because I noticed it was rubbing under her front leg and I wanted to give it a chance to heal and I just noticed that it looks like this? It doesn't seem to bother her or hurt her to touch it. Is it just healing from where it was rubbing?

Side note: Her harness isn't tight on her. I'm very picky about stuff being too tight because it bothers me to think she's uncomfortable or choking.