No. The only time you would need an aftermarket cooler is when you want to overclock or your stock cooler fan is going bad. 50-55C while gaming is safe & healthy.
If you notice your temperatures are going higher in the future, it's probably because you have dust in your heatsink, or your thermal paste is bad. To fix those problems, just unscrew the cooler and clean it with compressed air. Also, you will need new thermal paste, too. It's pretty cheap, about 5 dollars on average for a decent one. Before reapplying the thermal paste you will need to get rid of the old, dry thermal paste.