I used a DIY regas kit a few weeks ago. It worked but a few days later i removed the low pressure port cap and noticed green dye inside it. I cleaned it and put it back. Now today i was doing stuff and i noticed more green dye, this time on the outside of the low pressure port cap. Ive used the air con a few times and it still works two weeks after regassing it.

But, why would the dye be there? On the outside?

its a slow leak the neons dont hold much r134a enough so you can lose some and still have air but you will notice a loss in a/c you shouldnt loose and r134a out of your system

Well my low pressure cap seems a bit bent and doesnt fit very well, i read elsewhere about someone leaking from their lpv and they just got themselves a new cap and it stopped the leak. I dont know where to might buy a new cap from though, even normal Neon parts are hard to find here

I've noticed the same problem on mine after recharging and I'm wondering if the valve on the port is not closing completely and slowly letting the refridgerant out, and the leak detecting UV die is just pointing it out.

yes that is true the cap is a seal to the system but shouldnt be that noticable i have an entire ac setup if you end up with a different problem