She walked about two miles a day, cheered on by her husband Dan and their 13-month-old daughter Maisie, and her parents.
Lomas will not appear in the official results and did not receive a medal when she finished as competitors have to complete the course on the day of the race to qualify for a medal.
But a dozen other runners in the race have given her their own medals in recognition of her achievement.
Lomas, who now works as a jewelery designer, raised more than £86,000 ($140,000, 107,000 euros) for a charity which funds research to develop treatments for paralysis caused by a broken back or neck.
"I have had tremendous support since my accident which I am so grateful for, some don't have that," she said.
"Some people lose the use of their arms as well. A cure needs to be found."
The £43,000 ReWalk suit, designed by Israeli entrepreneur Amit Goffer, enables people with lower-limb paralysis to stand, walk and climb stairs through motion sensors and an on-board computer system.