I'm on nexplanon and had sex with a condom 9 days ago, and yesterday. today, i had pink discharge when i wiped. i'm really scared it's implantation bleeding. yesterday, the sex burned. what could the blood be from?

Most often: implantation bleeding doesn't occur at all. When it does, it is usually just a very tiny amount of blood. If it burned when you had sex yesterday, the blood might be due to a small abrasion (especially if there was inadequate lubrication). You might have breakthrough bleeding. You can take an "early" pregnancy test now or wait about 2 weeks to take a regular home pregnancy test. Try not to worry