I'm going to merge this thread with your original one. It's less confusing for others who might want to comment if all the subject matter concerning one topic is kept together in one thread.
With the prolapse, one thing that could help and you could ask your vet about, is applying granulated sugar. It can help draw out moisture and shrink the prolapse. If it's not too severe, hopefully it can help reduce it significantly. Though you will need to monitor your bun and make sure he doesn't ingest the applied sugar as you wait the appropriate amount of time for it to draw the moisture out, then clean off the sugar when done. And I see that the vet prescribed a protectant to help keep the exposed skin moist and from drying out, which is extremely important.
https://www.med.umich.edu/1libr/MBCP/ReduceYourRectalProlapse.pdf
https://rabbit.org/ailments-of-the-...that-anal-blood-or-protrusion-to-your-rabbit/
In addition to cutting out pellets from the diet, I would also not feed any other sugary/high carb foods. The pellets may have been a possible contributor of the irritation and prolapse, as the sugars and grains in pellets are often a common culprit of GI irritation for rabbits with a sensitive GI tract. And baby rabbits in particular can be very sensitive to food changes and possible negative effects of carbs introduced into the diet, as they don't process carbs as efficiently as adults, and this can lead to possible pathogenic bacterial overgrowth and GI problems.
I would also ask your vet if they did a fecal float test to check for coccidiosis and pinworms. You shouldn't have to wait for this test as it is just a fecal test that can be done in their clinic with a microscope, and doesn't have to be sent away to a lab. Coccidiosis and rabbit pinworms would be the two most likely intestinal parasites to cause intestinal problems in rabbits. Even though your bunnies symptoms don't entirely match up with these, they are the most common ones to affect rabbits and would be the first ones to rule out.
MediRabbit (coccidiosis in rabbits, link contains graphic medical related photos)
http://www.medirabbit.com/EN/GI_diseases/Parasitic_diseases/Pass/Pass_en.htm (pinworms in rabbits)