There are many ways to tighten skin but increasing the size of the facial muscles may be counterintuitive. Even if you could make you facial muscles bigger AND they would fill out the skin overlying them, your net result is a smoother skin surface but a much fuller face. While your skin is smoother, your face fuller = bigger. Is this what you want? I don't think so.
There are technologies that are not surgical that can tighten your skin without making your face look fuller. Companies are providing devices that respond to your primary concern = smoother skin. These devices focus on your concern, tightening one's skin. They are not ablative, which means that you do not have to deal with the recovery of a laser skin resurfacing. Hope this helps!