Botox for gummy laugh without changing my relaxed smile?

Great question.There are multiple facial muscles that act on the lips when you smile.There are muscles that act at the corners of the lip of widen the mouth and elevate at an angle (zygomaticus major and minor) leading to the characteristic smiley face.However, there are also muscles that act on the more mid-portions of the upper lips to elevate it vertically. It is this muscle group (levator labii superioris alaeque nasi) that requires slight weakening to avoid gum show while smiling. A small amount of neuromodulator (Botox, Xeomin, Dysport, Nuceiva) properly placed will reduce the pull up effect of that muscle to reduce gum show.Hope this helps

Yes, Botox only works to reduce the excessive inward curling of the top lip during spontaneous laughter or exaggerated smiling. A relaxed smile will remain the same, as this does not require excessive muscular use.