Answer by  
                                                                                          sanityrose (2664)
                                                            
                          
                          
                                                          Your rabbit may have an abscess or infection if they have swollen-red hind legs. The loss of a nail  indicates a loss of circulation. Try to look for any large bumps on the leg (it may feel like a blind eye pimple would on a human. A busted abscess will be visible. Care is needed to keep the rabbit alive.