Should I be looking for another vet?

Hi,

I have a situation that has been weighing on my mind, and I wanted to get the forum's opinion. My JRT had minor surgery to remove an object that had lodged itself in his paw. Surgery went fine, and after a 10 day recovery period, my little guy went back in to have his stitches removed. Well, even after their removal, he kept favoring the paw, and licking the digit where the incision was. It must have been really irritating him, because he gave himself a sore. I happened to look in between the paw pads, and discovered that they had missed a stitch. I took him right in, it was removed with apologies, but I'm still a little upset. My poor pup was miserable an extra week because of the mistake, and the sore is still healing. Is this something that never should have happened, and should I switch vets over it? Or is it just a mistake that can happen to anybody? I just don't want to ignore this if it's really something that points to possible negligence. I keep thinking about what if something else happens down the line. Just in case you can't tell, I've a very overprotective "mommy" who loves her baby to pieces!

Thanks for the advice!