In addition to all the great advice you've received from the others, I have an interesting bit of trivia which you might either find amusing or useful.
Famous Hollywood Glamour photographer George Hurrell, IIRC, used what he called his "magic potion" that he would anoint his subjects with so they would get dazzling results from the shoot. The "secret potion" was actually baby oil which he carefully applied in small amounts in certain areas of the face to produce a sort of specular highlight(s) in just the right spot. It worked great and gave his work a unique look.
With the hard lighting and big negs of those times- expert retouchers were in great demand!