Took 0.5 klonopin 4 months into withdrawal

I’m a little panicked because I broke down tonight and took a 0.5mg tablet of klonopin. I haven’t had a single klonopin in 4 months, zero temptation. My withdrawal was horrible originally and I did a 5 day rapid taper inpatient in the hospital. My question is will taking 1 dose set me all the way back to zero? I have zero intention of taking another dose, I just took it for a breakthrough miserable panic attack. I wish my brain could tolerate PRN doses every few weeks or so, but from what I’ve read that isn’t possible. So will one dose undo all of the work I’ve done?

A one off dose shouldn't be a problem, the bigger issue is you still have them in your possession, if it were me I'd dispose of them so you won't be tempted.  You're right, once we quit these drugs many of us can't go back on them, even taking them occasionally can cause what is known as kindling.  Take a look at these definitions because I'd hate to see this happen to you.

 

Kindling - The Alliance for Benzodiazepine Best Practices

https://benzoreform.org/kindling/

 

Kindling - Benzodiazepine Information Coalition

https://www.benzoinfo.com/kindling/

 

I quit cold turkey too which is basically what you did so I know how you're feeling, but it gets better.