A speculum exam can itself cause a small amount of spotting or discharge afterward, so brown tinged discharge the day after yours is often from the exam rather than a new problem. Your cervix measuring 2.7cm today, close to 2.9cm last week, is still a reassuring length and well within normal variation between scans. The hematoma shrinking and the placenta migrating away from the cervix are both genuinely encouraging signs for this pregnancy.
Next Steps
Keep taking your progesterone and antibiotics exactly as prescribed, and please continue to see your obstetrician for close follow-up scans, since they know your full history and can track the real trend over time.
Health Tips
Go in the same day if you get fresh red bleeding, fluid leaking, worsening pain, or fever.