Just to understand, I do not see the possibility of short selling on exchanges...
if you can not hold any longer, then maybe short is your best option so you can buy in lower price but for me, i think its good to still holding coins while the price is down and maybe i will buy in lower price again. or if you are trading in poloniex, you can find there is a lending option to lend your coin if you want to make another coins because i think it might be work for you.