Taking the test apart affects drying times and causes evaps.
Retest in a few days using FMU. 7 dpo is a little early tbh.
Is 7 days dpo too early to test?
A home pregnancy test won't provide accurate results at this stage. Why? Pregnancy tests measure the amount of the hormone human chorionic gonadotrophin (hCG) in your body. Your body only starts producing HCG after it's implanted, and levels at 7 DPO would be too low at this stage since the egg was just implanted.