I was using a multimeter and i touched the probes ,can they be toxic if they are used a lot?

MULTIMETER: SWEET AND SIMPLE - NO - UNLESS THE METAL IS FLAKING AND YOU GOT SOME OF THE FLAKES ON THE FINGERS AND YOU PUT YOUR FINGERS IN YOUR MOUTH AND SWALLOWED THE FLAKES - THEORETICALLY IF YOU DID THIS A LOT THEN YOU MAY HAVE AN ISSUE

Some basics: The skin is a tremendous barrier to any inanimate object like a probe. Nothing will get through it unless the skin is broken. If you stick a probe into something toxic & then put it in your mouth, where the tissue is designed to absorb stuff it may carry toxic material into your body. It is not how often they are used, it is how you use them that defines risk.