Mesh got damaged while modeling My Mesh is damaged as shown in pic, I was modelling a Dinosaur and could not see other side, but suddenly when i checked there is some damaged mesh shown in pic. I was using Sculpting before that. Can anyone tell what is the problem in it ?? I have uploaded the blend file here - 
https://filebin.net/wnzix0e6s7s23bk8/BabyBoss.blend?t=aegqgh60

I am learning blender and not sure where i did mistake, can you help me how to rectify?
With such a complex model, you should find the way to make a loop cut in the middle of it (down the spine of the animal). Eliminate the damaged side and use a mirror modifier. That should fix it and help you go faster overall.