hi Antonio
sorry to hear how much stress this is causing you
a few things that may help
1, here is ta pretty good collection of bartonella rashes / streaks ( they tend to look like jagged zig-zag lines - a bit like lighting strikes - or wavy lines - that are typically red or purple - and are called "striae" ). Hopefully when you have looked at a lot of them - you will see their characteristic patterns and i think will be able to distinguish them from other skin markings
https://tinyurl.com/24k2b4y22, other than the fact they are quite a useful diagnostic of bartonella ( do you have them in other
locations as well ?? stomach, lower back, armpit, thighs are common
locations ) they are not really harmful in themselves - and usually fade over time - so i don't think they constitute any great risk to your manhood if you see what i mean.
so if you already knew you have bartonella - the rash in itself doesn't mean anything
if it is a bartonella rash - and you didn't know you had it - its a good thing that you now do know and can approach treatment accordingly.
hopefully that puts your mind at ease and answers at least some of your questions.
i dont particularly want to look at your undercarriage - but my email is in my profile page if you are still worried
all the best !