My exams start in 20 days have I left it too late?

I have only done drips and drabs of revision on and off over the last few weeks but I have looked through lecture notes and past exam papers and I dont understand a single thing I am ****ed!!! I have had liver problems over the last couple of months even though I havent missed too much lecture wise I do have a ongoing illness. could I get extenuating circumstances possibly?? I was thinking I have 82 lectures so in theory I have about 82 hours worth of revision to do so if I did around 8 hours a day for the next 10 days I would revised all of the lectures which would give me 10 days to go through past exams and books before they start. Is it possible for me to pass my finals despite leaving it so late?????