You did the right thing by not applying the Duofilm (a caustic agent) on the face. Facial lesions whatever they are need to be treated under strict supervision. Without clinical photograph or clinical examination, I can only speculate on various possibilities. Freckles are usually numerous in number on the face and are in different shades of black colour with irregular margins. They become darker on sun exposure, hence photo protection with sunscreens is advised. Lentigenes is another close possibility, but these lesions are uniformly dark, well demarcated, generally many in number. These lesions are flat lesions and are not raised above the skin. Dermatosis papulosa nigra is another possibility in young persons. Of course warts especially pigmented plane warts can be confused with them. Both these conditions produce slightly raised skin lesions. In case of doubt, a skin biopsy can settle the diagnosis. With these facts in your mind, you may consult any other dermatologist.