Penis metus colour changed

Hi.. tip of penis colour becoming brown i talked to walking clinic and they told me everything is alright but its look different so anyone have any ideaHi.. tip of penis colour becoming brown i talked to walking clinic and they told me everything is alright but its look different so anyone have any idea

So yes, this kind of thing can be natural - while there are different circumstances that can cause this - for example, if you do a great deal of physical exercise, such a training very regular for an active sport, gym workouts and suchlike where you are sweating a great deal of the time, this can eventually lead to this happening.
Most commonly it is a variation in skin pigmentation which can happen anywhere on the body, including for some, on the face. So pigmentation change is very common on the genitals, and obviously this is the most likely explanation.
However, there are also conditions that can cause this - none that I am aware of are problematical. The most common is perhaps Seborrheic dermatitis - again this is more common on the scalp, forehead, in the middle of the chest and often on the genitals.
The specialist that would give you a definitive diagnosis is a Dermatologist

when did it happen? any trigger? oral sex etc

no oral sex.. few weeks ago it happend