I'll give some examples; I don't think spot can mean "dot" though. - I can't get this spot off my pants! (a small area) | point doesn't work - This is the spot. We're here guys! (a physical location) | point sounds weird - This massage is great; that hits the spot. (a location on the body) | point doesn't work - Will you spot me? (a verb for weight-lifters) | point means s/t else - Don't touch that spot; it's dirty! (a small area) | point means s/t specific; for example, the tip of a sword ___ - At this point, I knew I won. (a point in time) | spot means physical location - a point in time (a moment) | spot doesn't work - You're missing the point (the message/purpose) | spot means s/t else - A triangle has 3 points (dot) | spot doesn't work - Point me in the right direction (verb) | see "spot me" above Hope this helps!

both of the words mean dot. but when i can use these

Multiple meanings for these words. In what context or way do you mean?