Hi Sally –
To the best of my knowledge, white spots on tomatoes are caused by the following:
Stink Bugs – A serious problem for vegetable, fruit and other farm crops, stinkbugs feed by piercing fruit which result in blemishes or pale-yellow irregular patches.
Sunscald – This is essentially what it sounds like, a sun-burn, tomato style, and it occurs when fruit is too exposed during hot weather. To prevent this problem, be sure to leave adequate foliage on plants when pruning or use shade cloth.
I’ve attached a couple of links that should help.
https://www.planetnatural.com/pest-problem-solver/garden-pests/stink-bugs/
https://www.planetnatural.com/tomato-gardening-guru/pests-disease/
Good luck!