If you lost 90% already, I think it's better to hodl.  10% is not that big and is as same as forgetting it for future holds.  Or maybe you can trade while holding it.  The main concept is to increase the quantity of your coins. Sell them but make sure you can buy low with the proceeds so that you can buy more of the same coin.  But this is critical and you should watch the market often as you can or you may really sell it and never bought at lower price again leading to realization of loss.