I have a very sore throat and ulcers on my uvula and tonsils. My culture showed group b strep. And my doc says I don't need an antibiotic. Still hurts?

Find another doctor. I would treat you with antibiotics. Even if your primary infection is viral I have found that antibiotics can help prevent bacterial superinfection.
Strep pharyngitis . Pen vk is the treatment of choice. Clindamycin if penicillin allergic.
Correct. Group a strep is the only type that needs to be treated. Strep is actually a self limited disease, and is only treated to prevent rheumatic fever. Treating other forms of strep infection with antibiotics is unwarranted. I do not believe in the prevention of super infection. The inappropriate use of antibiotics leads to resistance.
Tonsillitis Antibiot. If your cultures showed a bacterial infection, adding an antibiotic will prevent complications of the infection. Go see another doctor for antibiotics. While only strep throat can cause rare events like rheumatic fever and kidney infection, any bacterial infection can have "infectious" complications. Antibiotics generally prevent these complications.
Group B? If you have group b strep in your throat then you don't have strep throat and likely don't need antibiotics. Group a strep is what causes strep throat, rheumatic fever and other complications.
Viral causes? Group b strep in the throat may not be the true cause for your symptoms. It's not what causes "strep throat", that's group a strep. Perhaps your doctor thinks you have an enteroviral infection, those can cause oral ulcers.