Good Morning and welcome. I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
If this swelling and discomfort is not due to Lady's glands, then this could be due to a tumor, infection or an injury that you were not aware of. Also, the anal glands can become infected which may cause the entire area of the anus to be red and irritated causing Lady this discomfort.
For now, apply a cortisone creme to this area every 4-6 hrs. This will reduce inflammation and help ease her discomfort. If Lady is eating well , give her aspirin at 5 mg per pound every 12 hrs to reduce inflammation and ease her pain.
If this continues after this treatment, have your vet examine her....she may require antibiotics or further diagnostics to determine the cause for Lady's distress.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please Reply so I can clarify for you
Sincerely, XXXXX XXXXX