Severe ankle sprain 8 days ago. Still can't walk, top of foot numb, bruising severe. How long should take to heal? Can I damage further trying to walk

Ankle sprain. Normal healing of a sprained ankle takes several weeks (on average). If its a chronically sprained ankle with constant pain and instability, it will take longer than a "normal" sprain. Yes, a sprain can get worse. Usually 3-4 weeks of rest, icing, antiinflammatory meds (like advil (ibuprofen) or motrin), bracing or compressing wraps, with or without physical therapy should be normal. Hope that helps!
Need to get it check. Make sure you see a specialist to take x-ray and possible MRI if suspect major ligament tear. Spain's can very in healing but average is 4-6 weeks. It should be immobilizes and elevated. Since numbness is involved together it checked asap.