Penis tip has brown patches

does anyone know what this is? File size is too big

here’s an image

Variations in skin pigmentation is a common issue and several health issues can cause this - I think the most common for genitals is Vitiligo.
However, there can also be a more simple explanation and this is dependant on whether you sweat quite a lot on a regular basis. So you may wear clothing that encourages sweat to build up in your groin region. The other common thing is if you do active sports and you do a fair bit of physical training on top of that, or perhaps gym workouts regularly, or perhaps something like riding a cycle where you are training quite a lot of the time? Anything that causes regular moisture to be present in the area can be a cause …

wouldn’t vitiligo make the skin lighter?

Usually …