I have tiny red marks that looks like someone potted a dot of red marks on my cheast all over my legs and some on my arm, mostly my cheast and legs and I'm 49 yrs old.

I also have these tiny red marks, which I have had for years,mainly on the stomach. They don't bother me at all,I have however noticed over the years they are increasing,but still only on my stomach area.

I don't think it's anything to worry about, maybe an allegy... new soap, deodorant,washing liquid, clothes softener or maybe a food/drink, that you could be allegic to.It could be almost anything,if it is an allergy.There are test that you can have done via your GP.

Have you any animals?. cat dog etc, maybe they have fleas, which you can easily treat,powder or spray from the vet or sometimes over the counter at the local store.
Has a friend or neighbour recently visited you who does have animals, or perhaps you've recently borrowed clothes from a friend or relative and there washing liquid or softener irritates you or they have pets etc.

If you feel that none of the above apply, and the spots are becoming a problem,the best thing to do is visit your GP,whom I'm sure will be able to help.