Reducing the thickness in the nasal tip skin can be only one part of rhinoplasty to change the appearance of a bulbous tip in the African-American patient or any rhinoplasty patient with thick nasal tip skin.
Thick nasal skin can be thinned in some instances to reveal underlying nasal tip cartilages that are beautifully shaped. This can be, but rarely IS, the only thing that must technically be done to refine a bulbous, thick-skinned nasal tip. Most often one must refine and strengthen the tip cartilage complex in some way using shaping and grafting and suturing techniques in order to support the skin, even when it has been thinned.
A plastic surgeon who specializes in rhinoplasty (many hundreds of rhinoplasty cases, leader in the field of academic and cosmetic rhinoplasty as noted not only by peers and publications, but by patients) will be able to evaluate your nasal tip and in great detail describe what the best technique for you would be. The Rhinoplasty Society, related groups to the American Society of Plastic and Reconstructive Surgeons, is a Society where one can not just join, but must peer review and meet certain criteria before being invited in. I have been part of this group since its conception and will be happy to help you find a capable surgeon in your area.
There are some cases of a disease which thickens the skin of the nose, but as you have not mentioned that, then there is some technique that will be applicable to help you have a thinner skinned nasal tip.
I might add, however, that changes in a medium thickness skinned nose, take up to 1.5 years to show the planned outcome. This time frame can be lengthened for someone who has a thick skinned nose. Therefore, patience for attaining final pleasure is as necessary a component as is finding a qualified surgeon.