If the trigger is pinching your finger, try rounding-off the back corners of the trigger slightly. It is this sharp edge that is probably grabbing your skin, holding it in place, which then causes the pinch. If you don't know your way around inside an S&W, let a 'smith do it!
If you want the face of the trigger to be farther forward, that can be accomplished by welding-up the face of the trigger. Mas Ayoob had this done to a Kahr trigger, but I read the article long ago, and don't recall the 'smith who performed the work. Of course, adding mass to the front of the trigger would mean less room inside the trigger guard for your finger. I don't believe a Fitz Special-style removal of the front of the trigger guard is currently considered the safe thing to do, but a talented 'smith could certainly enlarge a trigger guard, at least with a carbon steel weapon.
USFA has made single-action sixguns with enlarged trigger guards, compared to the SAA pattern. I mention this for reference, as a place to see an enlarged trigger guard; they don't modify other makers' guns.
Oversized grips, which enclose the backstrap, will move the web of your hand to the rear, which means less fingertip protruding past the trigger. This may eliminate pinching all by itself, but it makes your gun virtually as large as a K-frame.
Some of these thoughts come from my pondering of having an SP101's trigger face built-up, and having the trigger guard modified, the object being to give an SP101 nearly the trigger reach distance of a K-frame. Of course, welding stainless steel is more complicated than with carbon steel, and it simply makes more fiscal sense to just find myself a good snubby K-frame.
