56 year old male from Glasgow , GPP & Metformin

Can anyone assist please if you know about if Metformin does actually help with psoriasis including pustular (GPP) ? As well as having pustular psoriasis and a continuing (GPP) albeit it has calmed I am also diabetic type 2 and find my blood sugar is all over the place since this flare and even when I eat the pustules become inflamed and more risen with hot itchiness, with that I also have new pustules daily and was wondering if Metformin could help me with both conditions? My blood sugar in morning first thing should be between 7 and 8.5mmol but last week it was 18.6mmol with very little to eat night before but the flare has been bad last few weeks and not sure if it's the flare up that's messing with my bloods , just wanted to know if anyone has had same problem and if Metformin does actually help with all psoriasis types ?