Hi Carabelle
What sort of Evorel patches have you got? Evorel conti or sequi (if the latter then you would start with Evorel 50)? It does happen that some women suffer side effects when they first start taking HRT - and headaches are very common. These can be due either to the sudden rise in oestrogen or the effects of the progestogen (if you are taking Evorel conti). Hopefully yes, as your body acclimatises the headache should ease. In the meantime hopefully you have some painkillers - don't be afraid to take them for 24 hours....(or a bit longer if needed).
I hope it's better today!
Hurdity x