Hello, I'm Dr. Deb and will do my best to help you today.
I'm so sorry that Princess Doodlebug is having these issues.
I have a few suggestions which may help with her inflamed and irrigated rectal area:
1. Since she's such a small dog, you could soak this area in a warm Epsom Salt bath for 5-10 minutes several times a day.
2. You could gently clean the area twice a day with over the counter dilute Betadine or Iodine (to the color of weak tea).
3. Then, once it's dry, apply a small amount of over the counter, human cortisone ointment such as Cort-Aid. Just distract her so that the ointment has time to be absorbed.
4. Another perfect product for this situation will be Vetericyn Spray which can facilitate healing of just about any skin problem. It doesn't contain alcohol so won't burn or sting and is non-toxic if ingested.
It's often available at local pet/grain stores or can be purchased online (with overnight delivery).
In most cases, the above will be sufficient to sooth the irritated rectal tissue. Deb