Hi there Catspelle - the progestogen on that HRT patch is derived from testosterone so this could be what is giving you acne. There are other patches with a different type in them ( Femseven) but apparanetly they are in short supply. Your other option is to use a separate oestrogen patch with a progestogen = there is one called Provera (MPA), or else actual progesterone.
Here is what it says on this site about how close to testosterone they are:
Progestogens which can be used cyclically are of 3 main types:
Testosterone derived - Norgestrel, Norethisterone acetate and Levonorgestrel.
Less testosterone related - Medroxyprogesterone acetate(MPA).
Least testosterone related - Dydrogesterone and Micronised progesterone (Utrogestan).
I presume you have been given one with progestogen in it as you have had endometriosis? If not then you don;t need the prog and your problems will be solved!
Hope this helps?
Hurdity x