Feeding
 

Hes a green carpet and he gets fed brine shrimp, mysis, black tiger shrimp
The pink tip i think might be from hati

Ideally the nem should have stayed in the same tank where it split until it had time to heal. For now, until it forms a new mouth, it can't eat but it can absorb NO3 from the water, and use light as nourishment. Unfortunately it sounds like light is a no go too. As it is, it may take a while to heal with 2 of its 3 sources of nourishment impaired. For now if it was mine, I would leave it a couple more days, maybe a week total since you first put it in the tank. Between splitting and moving, its had a pretty adventurous time. So keep an eye on it for the week, to give it time to relax, maybe it will come out on its own. If it wont come out, use the powerhead trick to get it to move. The added light will help a lot in recovery, especially if you have low NO3.

Well it started to move out of there and it is now outside the cave, so good sign :) it is not getting any smaller, if anything I thing it looks a bit bigger. It also have nice round bubble tips.

Now I just hope it will not sting any of my corals.