Help??

Okay so I took this test yesterday, I could see a vvvvvvfl within the time frame, anyways I left the test for a few hours and had another look at it and the ‘vvvvfl’ is now a proper pink line (still faint but so noticeable) pic below....

So my question is, does a vvvfl get darker as it dries if it’s a true positive? Or do I just have a nasty pink evap?