ITB Knee Pain and Marathon?

I have a marathon in 2 days, rather than pull out completely I've decided to walk it. But I have ITB pain in my right knee that tends to set in after about 5km. I have been stretching the area but the progress is slow. What can I do to help me get through the day? Painkillers? anti-inflammatory? Any... show more I have a marathon in 2 days, rather than pull out completely I've decided to walk it.
But I have ITB pain in my right knee that tends to set in after about 5km.
I have been stretching the area but the progress is slow.

What can I do to help me get through the day?

Painkillers? anti-inflammatory?

Any ideas are welcome.
Update: I have some ibuprofen and diclofenac also codeine. What would be best for during exercise.
Update 2: Or maybe a Knee brace? anyone had experience with these and ITB problems.
Update 3: Thanks doc
It's for the Auckland (NZ) Marathon
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