an update, bought anti finrot and fungas medication on monday. Did a 25% water change and added meds. today the Cory with the most damage isn't looking to good. Seems to be off its food and pretty unbalanced too. the other Cory has a tiny little 'cotton wool' patch on its side. so i think the meds that you recommended were right.
I gave a dose yesterday morning and then do i give another in 7 days time if there are still signs. Also what are the chances of either of them making a full recovery. The one that isn't eating ahs no othert signs than fin and sclae damage, there are no 'cotton wool' like symptoms