My mom has skin colored bumps right under her eyes and she thinks the sun has caused the... what are they & did the sun cause them

Hello and welcome to EmpowHer,
Your mom could possibly have Syringomas or Milia which both look similar to what you described. They are both treatable to not related to exposure to the sun.
However she will need to see a dermatologist to receive an accurate diagnosis. If she is not properly diagnosed then she could try the wrong treatment make it worse.
Below I have pasted a link to a HER article that discusses 6 possible causes for bumps under the eyes.
https://www.empowher.com/skin-hair-amp-nails/content/eye-bumps-6-possible-causes
Faith