Hold and wait. If the price is good then you sell if it's low you buy. But it reallt depends on how you manage your investments.
You always be in a positive position, when its spike up then better to sell it out and enjoy your earnings when it spike down then do your stop and loss then buy back afterwards, especially when you really believe that the coin you supported have a developing team behind as the downfall is just a temporary act before it will regain and bounce back to another height, always do your research before dealing with your decisions make it much better to assess the value and how will you take the advantages.