How long it takes to get it back under control depends on so many things. If the stressors are ongoing, it probably will take some reduction in things causing stress. It also depends on the support and the skills for coping that each person has. Therapy for personality disorders can take several years for the person to learn to accept who they are, why they are that way, and learn how to change and manage symptoms even during the hard times.

Everybody is different. I tend to have crises that can last 1 week, 3 weeks, 6 weeks, etc. when triggered. For some people it blows over in an hour or less. I've been to eight different therapists, and have been with the current one for 4 years and have at least a year to go. I think I deal with things okay most of the time, but I just lost my job and I think it was mostly them, but they blame me and I'm not entirely sure.

So, depending on the person, it can take hours, weeks, years, depending on how thorough and how triggered and how much support and what coping skills they have.