Class Trematoda: Infect the internal organs of hosts. Parasitic Can be endoparasites (live in the host) or ectoparasites (attach to external surfaces of the host. Size: ~ 1 cm to 10 cm Covered in an unciliated cuticle. Usually require 2 hosts to complete it's life cycle.
Warts are generally caused by a human virus known as papilloma while moles are generally related with age and caused by hormones and environmental factors. There are cases when kids are born with moles but in general moles on the face increase with increase in age.
Mole vs wart: Melanoma is an aggressive dangerous form of skin cancer. If something has been sitting on ur skin for sometime without any major changes I wouldn't worry at all. I doubt it's truly a wart because after 2 yrs it should disappear. Probably it is a mole or pigmented skin lesion.