So hard to say on recovery time frame.
The angle of the hit & the location on head, same situation can even vary person to person..

Angled impacts might be more likely to misalign your c1c2, upper cervical chiropractic can check that.. Top of head impact might jam the neck & vertebra so, some PT or chiropractic could help with that..
Up C Spine & NUCCA, National Upper Cervical Chiropractic Association have info on upper cervical

The following Signs and Symptoms may indicate Upper Cervical (c0-c1-c2) Injury
Up C Spine - A New Approach - Sign / Symptom Checklist