Is It Normal to Have a Vertical Neck Band at the Age of 25? (photo)

Thin people can notice the visible edges of the platysma muscle in the neck very early on. This doesn't necessarily have to do with the aging process, more your anatomy, but it is associated with aging, so I can understand why you would want to address it. Botox or Dysport can help relax the muscles so the tight vertical band is not visible. Since the average number of units needed is anywhere between 10 and 30, the price would be somewhere between $200 and $400 every four months or so. You mention you are underweight. If you have previously lost weight, then the bands could also be related to a little looseness of the skin. This is much less likely at your age, but if the Botox didn't resolve the problem fully, a skin tightening laser or radiofrequency treatment may be considered. At our office, we have seen good results with Ulthera in this area.

Normalcy is a spectrum - the mild band shown in the photo certainly can be seen at age 25. I would recommend conservative treatments with injectables as the first line of defense.

The picture shows an early platysmal band. The best way to approach this area of anatomy at age 25 is with a neuromodulator (Botox, Dysport, or Xeomin). Surgery is not appropriate at your age.  Although a number of minimally invasive techniques could tighten the skin, it is doubtful you will achieve much more improvement over your current baseline.