I took a test and a line appeared but it's colourless it looks like a dent but it's not and it's appeared when the was wet?

Repeat it.: When in doubt, repeat it. Follow instructions exactly and be sure kit is not expired. This goes for any home test. if this is a pregnancy test, retest now, and if negative, check again in a week or two.

Likely not positive: Distinct color bands appear on the control and test regions in a positive test. Colorless lines would be interpreted as negative, as would any accumulation of color/dye in the region between the control and results lines. Home pregnancy tests are very reliable, but if you don't get your period, I would do another one in 5-7 days. Good wishes:)