Playing football definitely has a chance to worsen the contusion since it can cause excessive scar tissue to form. Since you got a contusion in the first place I would suggest you ice the area (not directly on the skin) several times a day for about 20 minutes at a time. Icing the area and using a compression band like an Ace bandage would expedite the healing process. If it were me, I would wait for the bruise to resolve before playing again! Contusions (mild/moderate) usually resolve within 4-6 weeks depending on the severity of the contusion.
It would not be fully healed within a week so if you hit someone or get hit in the same area, the contusion will worsen. If you see that it is healed, it would be a light contusion so you shouldn't have anything to worry about. Use your judgement as I cannot see nor diagnose you. If it worsens, see a doctor.
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