Hello respected, I can understand your concern, well 2 types of common cancer that can affect commonly the forehead ,, bcc (basal cell carcinoma) scc (squamous cell carcinoma) and usually both carcinoma are ulcerative in nature(initially can be patch), will bleed on minor trauma, and may be occasionally painful, and will slowly expand . Another condition, like bowens disease also a type of pre malignant condition,should also be look for, many cream like 5 flouro urecil , imiquimod, can be tried but results are uncertain.. best is you go for surgical excision biopsy, and do get done , histo pathological examination for confirmation of diagnosis. Do take another dermatologist s opinion before going to surgeon,because skin cancer is not as that common, and your description is not truly in favor of cancer, it can be something else e.g. granuloma annulare (benign condition) thank you