I am not a fitness expert neither am I close to being one but I would like to share some recovery tips given to me, by a Pro fitness friend, some years back when I engaged in a long race. Take at least 4 to 5 days off before attempting to run again, eat more of protein rich foods, try swimming as water helps to soothe the muscles and this last one might be quite brutal but immersing your legs in ice cold bath really helps recovery. Kudos to you for the courage to attempt the marathon and above all the strength to go through it!