[EiresJason]

Whenever you use SetPlayerHealth, use this instead.

pawn Code:

SetPlayerHealthEx(playerid, 90.0); //example

And add this stock to your script.

pawn Code:

stock SetPlayerHealthEx(playerid,Float:health)
{
    SetPlayerHealth(playerid,health);
    PlayerInfo[playerid][pHealth] = health;
    return 1;
}

This way, your serverside health will equal the clientside health.

Don't forget to make your OnPlayerTakeDamage callbacks and everything use the new stock.