I do wonder how hard it is to add menthol to existing cigarettes. Will we see Head Shops where you buy a pack of cigarettes and on the counter are menthol drops

I do wonder how hard it is to add menthol to existing cigarettes. Will we see Head Shops where you buy a pack of cigarettes and on the counter are menthol drops you can sprinkle on, and it's all technically legal since they're separate products?