Hi Catherine, it wouldn't hurt to do another fecal check, but diarrhea in a puppy can be from so many things.
Food can be a big one, many bullies are allergic or sensitive to chicken and grains, and cheese is a dairy product which can cause gastrointestinal upset and diarrhea if they eat too much. My guys came from the breeder on Royal Canin, which is chicken based and also has corn and grains in it. My guys have allergies to chicken, salmon, beef and grains, and they are currently on Fromms Lamb and Lentil. Also feeding too much food van cause diarrhea, how much do you feed Otis? Puppies generally eat 1 cup of a puppy kibble 3 times a day until the age of 6 or 7 months, and then are switched to an adult food and feelings are reduced to 1 cup of kibble two times a day. I have the same problem with my guys eating everything in sight, these bullies think they're bully goats. My male Bulldozer loves to eat textiles, his favourite thing being sweat socks, he's swallowed 4 of them in the last 3 years. He also loves dish cloths, underwear, towels, blankets, and stuffed animals. We can't leave anything around, laundry has to be locked up, and he can't have any pillows or blankets in his crate. My female Blossom doesn't eat things in the house, (except cat food) lol, but she is like Otis and will pick up,everything outside, she eats stones, sticks, leaves, random food she finds, cigarette butts, wood chips and pine cones.
Im constantly pulling things out of her mouth too. Diarrhea can also be caused by something they have swallowed, diarrhea and vomiting are often signs of an obstruction. Could Otis have swallowed something you may not know about?
if he doesn't get better, I would ask the vet to check his tummy, and maybe do an X-ray. I hope he gets better soon, please keep us posted.