@markavfc40 screw the pain, suffering and all that, you didn't give up and have an experience you'll never forget! There's simply nothing quite like a death march... fair play.
That foot looks sore, so take care over the next few days not to aggravate it if anything is strained or worse. Regarding the next marathon in six weeks, you should try something like:
day 0: FM done!
week1: Recovery, recovery, recovery... minimal milage, just try and get your legs moving a little, 2-3 30mins run would be good with maybe up to an hour next weekend max, all at a super easy pace.
week2: More of above if you need it but other wise try get back to 60-75% of your peak milage.
week3: 90-100% peak milage.
week4: 100% peak milage.
week5: 60-70%
week6: FM
Try and get a little running in at your goal marathon pace in weeks 3/4/5 but above all just recover. You won't lose much/any fitness and it sounds like rolling your foot sabotaged you this time around.