i just noticed one of the knots has gone back into the grommet...
should i get it re-strung?
Perahaps you should, before the knot goes through the raquet. And next time put a bigger knot...
The racquet is cracked -- can't be restrung.
what makes you think the racket is cracked?
Regardless of whether you get it restrung now or not you will need to have the eyelet replaced at your next restring. Its not a simple indication that the racquet is cracked but it looks like you've got two different types of string. Are they both the same gauge?
Sorry to be so late, Sean. There are two cracks leading up to the grommet in the pics you sent. Play it out and give it a decent burial. :(