King Henry VI, Queen Margaret and the Prince managed to escape, eventually to Scotland. With them were Somerset and Exeter, who presumably had very good horses.
Many Lancastrians were less fortunate. Northumberland died of his wounds, which almost certainly saved him from the block. Wiltshire managed to get away from the battle but was eventually captured at Cockermouth (of all places) probably on his way home to Ireland. He was promptly executed.
Devon was also executed, along with more than 40 Lancastrian knights. Edward's mood was probably not improved by finding his father's, brother's, and uncle's heads still displayed over the gates of York when he arrived. Replacing them with Devon's was doubtless some consolation. (Ironically Devon had been one of York's early supporters.)
After this initial blood-letting Edward's policy became more moderate. Many pardons were eventually issued including ones in favour of Earl Rivers and Lord Fitzhugh. Rivers and his family seem quite genuinely to have changed sides at this time, perhaps swayed by Edward's personal charisma. Fitzhugh on the other hand is an example of a man whose heart probably remained loyal to Henry VI. He was Warwick's brother-in-law and from now on can perhaps be understood better as a satellite of Warwick rather than a devoted subject of King Edward.