In MMA there are alternative winning methods which decide a large fraction of the matches, even if hitting the head still remains the most frequent method for winning a match before the time limit (strangling is the 2nd most frequent, and unlike head knockouts it does not have persistent effects even when the loser fails to accept defeat, strikes to the liver are the 3rd, then joint locks and strikes to the legs).
Moreover, a MMA fighter has much more effective defense methods than a boxer, so a much lower percentage of the attempts to hit the head of the opponent are successful, in comparison with a boxing match. Also, the lighter MMA gloves do not allow strikes to the head as powerful as in boxing, because those would result in hand injuries.
MMA matches look more gory, because of frequent skin cuts, which result in bleeding, but those pose very little danger in comparison with the strikes to the head given with heavy boxing gloves, which do not produce visible external bleeding but they produce much more harmful internal damage to the brain.
In any case, sports like boxing or MMA are unsuitable for amateurs. They are acceptable only for professionals who are willing to accept the risk of health damage in exchange for a sum of money big enough to allow them an early retirement, hopefully before accumulating too much damage.