Bf put tip of penis in. No ejaculation. Started bleeding 7 days post intercourse. Implantation bleeding? Or early period?

Early period. Whoa there, bessie! Unless you want to get pregnant don't put any penis tips in! That "pre-ejaculate" has the most concentrated sperm of all, so you could get pregnant without ejaculation! Implantation bleeding is usually 2 weeks after ovulation, which is 4 weeks after the start of your last period, I'm going for irregular/early menses and no baby.
See below. Usually implantation is about 9 to 10 days afterwards.