Do faint lines eventually get darker?

Christina • Married to my best friend, we have a 2 year old princess, 3 dogs and 1 cat.

I saw a very faint line on this test, and kept it just in case I was pregnant (I kept my tests from my daughter).. well, my 2 year old pulled it out of the drawer and the line is darker. I understand it could be an evap, but I was just wondering if there’s a chance it was a faint positive, and just darkened up from sitting? Gonna retest in the morning.

Right after taking

Now