How long should I wait between Botox on chin and Xeomin for forehead?

If I get 20 units of Botox for my chin/mouth area how long do I have to wait until I can get 20 units of Xeomin for my frown lines? I only had Xeomin once, 20 units for my 11s and it's wearing off. I'm seeing a doctor for Botox for my chin (never had it before). I will go back to my original injector for Xeomin for my forehead. I don't want to overwhelm by body - last time I felt numbness everywhere in my body after Xeomin in forehead (everything went away in a few hours, I calmed myself down).