It looks like its pull back a little bit around the edges, as I can see the skeleton. Lobo are very hardy, just give it good water conditions and feed it and it should be fine. I would slowly move it up some, so that it gets more light.
Definitely a Lobo I had mine doing a similar thing. If you have a piece or small rock put it on the rock but keep it on the sand. This will prevent and tissue from touching the sand which I doesn't really like. And then just feed as said above. Feed often and regularly. Don't be scared to over feed it. Good luck.