Estrogen Cream Odd Symptom?

Hi everyone, I'm really hoping someone can help me out and tell me if this is normal or how to stop it/if I need to go back to my doctor.

I've been put on the topical estrogen cream for vaginal dryness and for the first week where I was instructed to use it daily it was working great, however after I dropped to twice a week I've noticed that the skin on the outside and where it stretches back to my bottom is back to being very tender and dry by the second day of no doses.

Do I need to be on a higher dose or to be using it daily? Or is there something else going on entirely? The relief I've had from this cream has been incredible except for this issue and I'm hoping you can help me get to the bottom of what to do next.

Thank you!