I think i have acute nasal vestibulitis, pain and small swelling of tip of nose started a week ago. when should i start worrying and see a doctor?

Nose swelling: If there is significant redness associated with this swelling, you should see a physician as infections in this area of the face are taken very seriously. The swelling may be a simple inclusion cyst or early pustule but since there is some pain, some degree of inflammation may be present and in that case it's best to be examined.