UV signature

Hi I purchased a UV Torch light just to have a look around my body. Too my shock I came across something that resembles day-glo paint , on doing so I couldn't believe what I saw and decided to scrub it away it has been placed at Eight places. I first tried a Green abrasive pad what are on the back of sponges used for washing pans etc. No avail all this did was make the areas sore around a Ten Days later I got some white spirit on cloth and rubbed vigorously again nothing. My next attempt was to use Petrol and you guessed it nothing happened the Day-glo paint that can be only be seen with the UV light will not budge. My last attempt last week in my opinion was getting desperate I used neat Bleach and again rubbed vigorously to No avail again. Ive got no idea what this stuff is. I have purposely not mentioned the actual Colour just in case it has some other kind of meaning however there are not too many common day-glow colours. Has anybody else come across this and if so what do you think it is for? I also urge anyone who has memories of being taken to check out your bodies every where and I mean everywhere. All kinds of ideas have been going through my mind as to what this is for...Thanks for reading..