Sometimes a less severe asthma attack will go away on it's own or at least seem to go away.
But the asthma attack can get worse if not treated. You should always get to the emergency room or call an ambulance if you have an asthma attack so they can treat you for the asthma attack.
Usually your inhaler will be enough to take care of the less severe asthma attack but if you have a more severe asthma attack always get to the emergency room asap or call an ambulance.
Asthma attacks can be deadly so always seek medical attention.