Lionel messi grew up with a complex growth hormone that prevented him from growing to his full height. Due to this he was always the smallest player on the field.
The medicine for his deficiency came at a harsh price that the family couldn't afford. He also had to inject himself with it a couple times every day. He was only 10.
At 10 he was wise beyond his age, he knew that this would help him reach the next level and that it was essential. He persevered through this and now he is one of the best in the world. His story is not unlike Salvas as they both had to overcome physical difficulties and they both turned out fine.