theultimatecomicmovielover:

Loki’s wounds should Look Familiar he experienced Thanos’s torutre firsthand when he fell into the void and was found by him and that’s why he looks so sad. He knew exactly what that pain felt like and what Thor was experiencing and he wanted to stop it. 

Those injuries may well be the result of torture of some kind, but not the same that Thor experiences. Thanos didn’t have the Power Stone in 2011. It was still on the planet where Quill goes to retrieve it in 2014.