How does one divert from unwelcome and inconvenient episodes their brain has decided it wishes to embark upon?

Cordial salutations.
I feel it is necessary to construct a brief exordium apologising for the predestined horrendously worded and nonsensical nature of whatever writing sees fit to come to pass. Will be doing my best.

As is often the case, I am being presented with the constant desire to set on myself with an array of blunt objects and sharp implements, and it feels there is somebody in my mind (‘tis always the same unfavourable being, it seems I know her well) showing me images of all the strange acts of mutilation one could perform. This also entails ridiculous things I would never do, like eviscerating myself with kitchen knives and extracting an entire network of blood vessels. (Apologies for the unsightly carnage and bloodshed references.)

I’m refraining from any excessive bludgeoning yet after erratic aberrations of either an excessively maniacal or sadistic and blood lathered nature, it – for one – takes too long to return to normality, and secondly makes me guilty: I do not feel it is warranted for me to waste time over such matters.

Thus, I wish to enquire after methods you hold in your knowledge/ experience that diminish the said occurrences.

I thankyou, and apologise if I seem self absorbed and have a complete lack of regard for anyone else; it is that I don’t want to waste time battering – or chasing after – myself that I ask. :)