I had my son at doctors yesterday and they said maybe chicken pox. however today hes come out in more spots but next to his mouth one has crusted. ?

Sounds like it: Chicken pox or varicella is known to come out in 'crops' of lesions-which will progress from a spot, to a pimple type thing, to a blister, then dry up into a scab. Hopefully not leaving a scar at the site, but it is possible. Most of the lesions come out over the trunk, but the face can be quite involved as well. There is a vaccine available which is for those 12 months and older. Follow up w/ doc

As expected: Cpx will usually come out in crops for up to a week (usually 3-4d). These can include in the mouth, around the mouth, around and on the genitals. They are shallow and keeping them clean aids eventual healing & reduces itching. They are contagious until the last sore has dried or 7 days after the first sore, whichever is latest.