Hello,
The greasy skin after hysterectomy can be due to hormonal changes. It should become better in a few weeks. But if it persists then get your hormonal assay done and if you are lacking them then you can opt for hormonal replacement therapy by oral means or by patch.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
You can have changes after this surgery. You did keep your ovaries so you're getting some hormones but, maybe not enough. Ask your Dr about hormone testing to see what your levels are.