I take lyrica (pregabalin) for mood and irritability associated with borderline personality disorder, can I take it as needed instead of every day? Causes munchies

Not clear. Lyrica (pregabalin) is approved to treat diabetic peripheral neuropathy, postherpetic neuralgia, partial onset seizures & fibromyalgia. It can take 2 to 4 weeks to get adequate pain relief. Off-label uses (which account for most prescriptions) include panic disorder, migraine prophylaxis, social phobia, bipolar disorder & alcohol withdrawal. I don't know of any studies showing dosing needs for bpd.
Not recommended. No personal advice can be given, but these types of medications need to build up and stay stable in your system to be effective, they do not produce immediate effects that would allow for prn use, and using it prn can cause loss of efficacy and worse problems. Some of these meds do produce weight gain and there are other meds you can ask you prescribing doctor about.