Hi there
I am not an expert on perfume infact I know very little, but from what I have been told, you shouldn’t layer 2 different brands on top of each other. If you are getting a head ache it could be an ingredient in the brand that is setting off an allergy. Check both and see if they have similar ingredients to each other aqnd here in may lie your solution. Also perfumes are made with particular oils that are blended together to provide a scent once each layer has setled therefore it’s not advisable to rub your wrists together when applying perfume because it disturbs the scents as they settle.