Well...first...glad to see you here..... Next....I would have a Doctor take a look and find out the route cause......if he says you could create a permanent injury without recovery then it is a skip the race..... If he says you can recover while running...then it is just a matter of what goals yu can be satisfied with.... Can you make yourself slow down?....WHen the race starts....can you hold back...? If you know deep inside that "slower" is something yuo can't do..then skip it...watch it...and look for your friends to cheer them on.... Last year I ran the half at OKC (a week after Boston)...I really hated to skip the marathon......but just couldn't so it.. I have no regrets....I was able to run the first 7 with a friend running his first marathon....then meet him during the last couple of miles and run it in.. I also looked for Paul (pfriese) and another friend that PR'd....it was a blast to see them having a good day... So watching can be fun too..... Good luck with your decision..