What does cancer in the big toe look like and does it appear over time from a black spot -looking like you dropped something on your toe?

Toenail discoloratio: Black discoloration of the toe under the toenail is usually due to bruising from repeated trauma from footwear. See a podiatrist for reassurance if you have much concern as the discoloration may last months.

I have a black spot: ...under my toe nail too, so I hope not. A melanoma can appear as a dark spot anywhere on your skin, including a toe, or under a toenail. Most often a black spot that looks like you dropped something on your toe is an old hemorrhage from trauma. Old blood should resorb or grow out with the skin. A melanoma, on the other hand, may have irregular coloration, an irregular border, and grow over time.