Since we don't know the exact process you went through for the application, I would say simply start over, do it again, and see if you didn't miss something or not properly do something in the application.
#1 - You should have fully cleaned the heat sink ( a high % rubbing alcohol works great ). By "reapplying", I assume you mean there was paste on it before, and it should have been completely removed.
#2 - Use a good thermal paste for the reapplication. This may come down to personal preference. I've used all the major brands in one build or another, and use only Noctua NT-H1 now. Just be sure to use something you trust.
#3 - Properly apply the paste. Most recent results I've seen from lab tests show the small single dot in the middle works best. Whichever method you subscribe to, remember....LESS is more. Too much thermal paste kills the good temps.
#4 - properly re-attach the heat sink to the chip.
Hopefully going through all the steps again will yield you good results. Good luck.