This is a tricky one. Compared to your standard connection at peak speeds, a VPN is likely to slightly increase your ping – but, if you're very near one of your VPN's servers it could possibly decrease it if you're lucky.
However, if it's a choice between not playing and playing with a usable, albeit not lightning-fast 100ms ping, we'd take the latter any day of the week.
To learn more about this, see how to use a VPN to speed up your internet.