Hi and thank you for using Petco Pet Education Center, formerly Petcoach! Sorry to see that Finn is having this problem. I see lesions or spots like this occasionally on dogs in the same areas. Most of the time these spots resolve without treatment but most of the cases I have seen are much more mild with fewer spots. I always wonder whether these are related to some kind of insect sting/spider bites, contact irritation from something in the environment, etc. Some of these lesions or spots can resemble small areas of hemorrhage too which could indicate blood clotting disorders and those causes can be numerous. I would advise your veterinarian evaluate these since Finn has a lot of them. I think that if he is acting completely normal you could monitor this and see if they resolve. So if he acts normal, eats, drinks, uses the bathroom normally you could just see if they resolve. If anything is different, he should be evaluated immediately. I hope this helps and I hope Finn gets well soon.