If an electric razor has a good sideburn trimmer,
sometimes you will be ahead to trim “difficult” spots on your face with the trimmer first
so that you only have to do one pass over difficult hairs with the main foils.

One brother’s wife had an electric “hair root zapper” tool that killed off some “wild hair” spots permanently on his chin.
Worked so well that he later asked her to do some ear hairs.

It has recently been discovered that grey hairs are caused by “senescent cells” in the hair root that used to make the protective chemical “melanin”.

These senescent cells ( called in the media “zombie cells”)
can be helped along to properly die off and be replaced by healthy new cells
by eating a big dose of chemicals common in fruits called flavanols.

Two such chemicals are Quercetin
(the flavanol most consumed by humans, common in most fruits like Apples)
or Fisetin,
(which is found in many fruits but most common in Strawberries).
You have to buy concentrated pills of these flavanols,
and consume a dose of 100 milligrams per each kilogram of your body weight,
and take this daily dose for 5 or more days in a row.