"By the way, my pimple broke ready and the swelling started to reduced. I think before tomorrow it will completely heal. Whats your opinion ?"
Sometimes a pimple is, well, just a pimple.
The groin area is subject to pimples. It'd warm, moist, has oil and sweat glands and is typically covered by clothing much of the time. These things can "pop up", especially if one shaves in this area and irritates hair follicles.
By the way, a pimple has nothing to do with HIV (to ease your concerns.).
Yes, I agree there is ABSOLUTELY no risk whatsoever.
As has been pointed out (and here I am assuming this young child is HIV positive...something that is highly unlikely) the virus simply cannot cross intact skin. Chapped skin, paper cuts, rough skin from winter weather, a sealed cut, etc...none of these are open portals into the body.
There is no reason to worry and really no reason to get tested whatsoever. Honestly.
No, you need absolutely no testing whatsoever. There is NO risk of STD transmission from any of this and no, because you had a cold at the time of the lap dance plays absolutely no role in any of this.
Your sexual contact with this sex worker (the oral sex) involved the use of a condom. Even assuming she was HIV positive (unlikely since the Amsterdam Red Light District requires STD testing on their sex workers) the virus cannot cross an intact latex condom).