Is there an effective way to determine if something is skin cancer. i mean, what should you watch out for?

For a mole: Aad malignant melanoma: asymmetry: 1 half is unlike the other. Border: irregular, scalloped or poorly defined. Color: varied with shades of tan, brown or black; or white, red or blue. Diameter: > 6 mm. Evolving: mole /skin lesion looks different from the rest or is changing in size, shape or color. An irregular mole that itches, bleeds or is painful is worrisome for possible cancer.

Skin cancer : Clinically, a small skin cancer starts as a small non healing patch or growth. Others start as as a changing or new mole that is typically but not always asymmetrical, irregular bordered , different colors, size larger than a pencil head eraser or that itches bleeds. See a dermatologist for a skin exam yearly or whenever a suspicious area develops.