DID I POP THE STITCH IN MY MENISCUS?! PLEASE ANSWER ASAP!?

I had acl reconstruction surgery / meniscus repair 2 weeks ago, and they put in one stich to hold it togther, but I think I popped a stictch walking on it without crutches, how would I know? I have a big insicion right at the bottom of my knee, and at the top of my shin, and the skin near it is raised, and I can feel a bump there. I lightly pushed on it, and it feels squishy. PLEASE HELP!