"You have to take care of your injury."
Translation:Tu dois prendre soin de ta blessure.
"Tu dois soigner ta blessure." would mean "You have to treat your wound.".
"Soigner" means "to treat" or "to take care over".
"Se soigner" means "to treat oneself" (ie self-medicate) or "to take care of oneself" (appearance or wellbeing).
"Il faut te faire soigner !" means "You should have your head examined!" (lit: "You should get treatment.").
Taking care of an injury involves changing dressings and keeping them clean and dry to avoid infection. Also avoiding situations which would put undue stress on the injury and risk making it worse. It does not require medical knowledge. It may involve carrying out procedures or activities prescribed by a doctor or physiotherapist.
Treating an injury requires some kind of diagnostic ability and may require medical knowledge. Depending on the severity of the injury it may or may not be possible self-administer unaided.
it seems impossible for me now to translate from English to French, I can usually get the right answer going the other way, but the further I proceed, the harder it becomes. I am making absolutely no progress. Any advice on some other language site? I am really lost now. Thanks in advance