Does any past injuries affect your dream bubble self? Like obviously kurloz's mouth is still sewed shut and meulin is still deaf but none of them are affected by the explosion that killed of them.

They still have those imperfections because those characteristics are a defining part of themself and they choose to keep them. Similar to why Terezi’s dreamself was blind and why Caliborn (if he did ascend) is still lacking a leg and tooth.