It's probably a prolapsed rectum. It looks like it may also have had diarrhea. You really need to get this kit to a knowledgeable rabbit vet right away. If it does have true diarrhea with no normal fecal balls being produced, that is an immediate emergency and needs the proper meds to have any chance of saving the rabbit. And the prolapsed rectum will likely require surgery.
https://wabbitwiki.com/wiki/Dysbiosis
https://rabbit.org/ailments-of-the-...ondition,persistently protrudes from the anus.
https://rabbit.org/vet-listings/