Inquiry about glabella Botox

I'm worried because I seem to have developed a habit of tensing my eyebrows whenever I look in the mirror lately, and I can see slight wrinkles even when I'm not doing anything. Would it be better to get Botox before the lines get deeper? Also, I'm considering fillers because the hollowness on the sides of my cheeks is quite severe; I'm wondering if getting fillers might make my face look bigger or unnatural, and how long the effects usually last.