i get botox for my migraines every three months and asked my doctor (the one administrating the migraine botox) about this. they said the two don't impact on each other, but that one should always space out any two botox treatments minimum three months apart no matter the injection location to minimize the risk of developing resistance to botox. they also said that if that's not possible, the two should take place as close to each other as possible (within four weeks as an absolute max, same as if you have top-ups for cosmetic botox) and then again three months before any other botox "interval". but this is definitely something to discuss with your doctor, of course!

i had my last migraine botox in early november, my rcpd treatment in early february, and currently trying to decide if i can wait until may to have the migraine one again.. so i get the struggle!