You can only get estrodiol gel on prescription and I don't think your doctor would precribe it just for facial use unless you went privately and they might make you up a much weaker solution for skin care. If of cause you are using estrodiol for HRT, you could always use a very tiny bit in some cream to dilute it.
If you go to Biovea UK and search for estriol-care you will find info and prices. They are a very reliable and trusted site, they also sell natural progeaterone cream too. Originally natural progesterone cream was sold as a face cream in smaller doses, years ago in America.
I get my hormones creams as well as supplements from Bioeva, hormone creams last a very a long time as I only use a very small amount.
Silverlady x