Unless you make yourself a lobotomy or seek solace in a bottle or drugs, but I do not advise you to go to that. The pain gradually subsides, associated with the dramas of the past.
The brain is not a hard drive, it is not so easy to remove something from it.
Any information (by itself) remaining in your brain has value. Emotional shocks, and nervous breakdowns, leave cognitive imprints, sometimes very aggravated, so that it interferes with looking ahead.
It usually just takes time for the neuronal system to build up a "patch" on each anxiety zone that signals problem.
If a person has thoughts like a "splinter in the brain" that come back to him again and again, sting him, and he does not want to feel them anymore, but they are intrusive, then you just need to weaken the emotional response from these thoughts. Any internal conflict can be resolved. If thoughts are confused, they can be collected, focused, and stopped being diffused. During dissociation, this happens.
The state of post-traumatic shock makes a person like a hunted rat, he cannot find peace, rushes around with bulging eyes, sometimes exhausted, psychologically broken for a certain time. This happens if a person's perception is too deep, intense, and after a physical injury, such as a car accident (for example), he tries to recover for a long time, to enter the same rhythm. This is already a more serious problem and requires a little rehabilitation. But one way or another, the human nervous system has the property of neuroplasticity, and this means that after even the most terrible trauma, the body almost always recovers.
Just take and forget something that is currently forming "mental pain" you just can't. The body simply signals a zone that is currently a systemic vulnerability. Sometimes it has external reasons, and most often they can be corrected. When there is an emotional connection, for example, with a girl who causes tremulous feelings, but she left and left long ago, a relationship with her is no longer foreseen, instead of climbing into the neck of a bottle, there is a method, something like tearing apart photos in her hands where she is depicted. Hands refuse, because she is still dear, if you overcome yourself and break, then the connection will partially weaken and stop.
When someone close and dear died, the situation is more complicated. It is important for a person initially not to have too strong attachment to others, to be accustomed to living himself in the role of a helmsman. Otherwise, the grief from the loss of a loved one is not always worth drowning out, because none of the psychologically mature people will ever tell you that all your feelings should be strictly pleasant and positive for your whole existence. This only happens in the fairy tale about Alice from Through the Looking Glass.
This is a cognitive trap, a person hopes to create an impenetrable shell so that he will not be disturbed emotionally, as a result, we are faced with just a cold piece of ice block, insensitive and indifferent to everything. Most psychic attacks take this kind of goal - to make the victim either disabled or hounded. A sober balance is possible.
The human brain records absolutely everything with which it comes into contact, but eatsb the ability to care and focus. In general, human memory in itself for many is desirable and longed for in the form of super memory, and people complain about forgetfulness. If desired, a person can do so so as not to remember what he considers unnecessary. Anything that a person does not want to fix, he can simply ignore, by distributing attention.