Hello! Thanks for putting your query in HCM. I am a Gastroenterologist (DM).
Anal stimulation with a wooden object may have either caused ulceration or perforation there. As only ulceration may not lead to fever. And may be due to perforation there may be fever. However it may be coincidence only that after anal stimulation you may have suffered from acute
infectious enteritis that has led to fever, diarrhoea and
blood in stool along with lower
abdominal pain.
So I will advise you to get Xray abdomen in standing position to rule out perforation. If it is not there then get stool culture and may start antibiotics empirically like
ofloxacin and
ornidazole, and keep hydration level well.
I hope I have answered your query and this will help you. Remain in touch and get-well soon.