I don't always have cysts on overis (3 out of 5 scans were okay) but blood tests for hormones are out of whack, I has tash, spare tyre, irregular cycles etc. So before they saw any cysts on scans they could diagnose me on bloods and visulas alone.
I was tested for diabetes many times as I oftern ended up at docs or ER from passing out and my blood sugar levels were always low when tested me - gave me glucose and I would be fine (or other times they'd be too high)
Yet all diabetes test came back normal or borderline.
Since been on Metformin I've lost 4 stone in weight with no change in food/lifestyle and my blood sugar has stablised. Not had a fainting fit for ages. Also not tired all the time - I can get up on a morning now. Also started to regulate cycles more.
So yes Metformin does more than help with cycles and no matter what happens I've been told to stay on it as it's proven to work so well for me (I refused to beleive it at first)
If you think you might have it hun push for more PCOS tests as not everyone with PCOS has cysts all the time if that makes sense. (last ER trip they said the sudden sharp pain I was feeling was a cyts and when it burts I'll be fine. 3 days later it burts - was yukky TMI down there then I came on and was fine)
ASo yeah even if have no cysts show on scans I'm pretty sure the sharp pains we randomly feel now are the cyts and when they burst we're back to not feeling them again.
Hope this makes sense.