The black spot in my heel in the beginning it was more internal spot, but now seem more superficial ( outer) , oval-shaped, like dry blood.

Probably nothing: From your description, it's probably nothing, but just to be safe, can you post a picture of it? If not, definitely see either a dermatologist or podiatrist for possible biopsy if you're concerned further.

Get a biopsy: See a podiatrist for a biopsy! it may be as simple as a blood blister, dried blood under the skin, or malignant melanoma.