Is There Any Danger If I Kept Tampon Inside For 3 Days?

I accidentally left a tampon inside me for 3 days. I was noticing black blood coming out of me and an odor, so I researched online and I read someone mentioning it was because she had left tampon in. Decided to check, and sure enough, there was one stuck way inside. I think I forgot I had one in and me and my boyfriend had sex and he pushed it way inside. I got it out but now I'm scared. I'm actually taking amoxicillin for an infection in my cheek, so maybe this will be enough for both problems? I am experiencing no symptoms of TSS. No fever or flu like symptoms and no rash either. Would a douche and the antibiotics I'm taking be enough?