While regenerating, you heal some HP at the end of your turn. This is one hit of Heal-element damage, does not receive bonuses from your Stats, has no Type, and always hits. The damage is based on the regeneration's Level:
Base: (round((5.25 + 0.5625*Level + 0.00375*Level^2)/2) * 0.1 Rand: (round((10.5 + 1.125*Level + 0.0075*Level^2)/2) + ((round(200 + 13.2*Level)/200) * [2.1462*Level + 10.399]† / 8))* 0.1 †Minimum 10, maximum 200, rounded to the nearest 5
Again, regeneration does not receive bonuses from Stats.
If your would start regenerating a second time, then the new regeneration either does nothing (if the new regeneration is of lower level) or replaces the old regeneration (if the new regeneration is of equal or greater level).