In response to IshimaruKenta. I am not trying to suggest that mucus and rectal bleeding could not in theory be caused by contaminants in tirzepatide, but I really cannot think of any possible mechanism that makes any real sense other than tirzepatide causing diarrhoea and the pr bleeding being secondary to anal abrasions or bleeding haemorrhoids irritated by the diarrhoea. In which case it is not due to contaminants just side effects.
In general rectal bleeding and mucus is something that needs medical assessment. Just because you are taking a glp medication does not stop you from catching a bacterial gut infection, from food, water, people or travel and the ones that cause bleeding usually require antibiotics. And then there are the other causes like bowel cancer and inflammatory bowel disease, which need to be at least considered and excluded. Most rectal bleeding is from local anal issues, which will heal up, but ignoring these symptoms is generally considered to be a bad idea, because that is exactly how you get diagnosed with advanced bowel cancer. I see at minimum stool cultures being required, if it might be infective, blood count and maybe colonoscopy. Sorry, they are not much fun.
So I would strongly recommend seeing a doctor.