This is a common problem in older Bichons. f there are a limited number of bumps/cysts that are getting irritated and bleeding, could they be removed surgically? This is often the best way to solve the problem. Bumps and cysts that are not getting traumatized can be left alone.
If the bumps are getting cut during grooming, clip around them by hand. This would help even if grooming is not an issue. Make sure the groomer knows where the cysts that are most easily traumatized are located.
You can soak the scabbed areas with warm water to get the scabs off. If cysts are under the scabs, the oily/cheesy contents can be gently expressed out. The cysts often get smaller for a while although they will refill eventually.
Let me know if you have follow up questions.