Hello. Post-hysterectomy a woman s body goes through multiple changes due to a sudden change in production of female hormones necessary for various functions. For this reason the estrogen patches were prescribed. The dryness around the area you have described (perineum) could be related to a hormonal deficiency, but this is only an assumption. This can also take place with various infection relating to the female reproductive system and also many condition relating to the gastrointestinal system. Thus, an accurate diagnosis can only be made after a physical examination supported by laboratory investigations. Please visit a doctor for the same. Hope this helps. Take care.