Being Saved from the Unforgiven...

As I have mentioned before, one of the greatness, and hazard, of pen and ink is its unforgiveness - the ink, once down, is THERE, and thus requires forethought in doing one's rendering...
however, if there is a mistake, a 'bloop' as it were, from the nib, despite taking care, it is possible to overcome this, with judicious use of white ink [at least on Stonehenge paper] and thus be able to continue with whatever rendering was in progress at the time... here is an example of the process, using FW acrylic artists ink...
it may require several rounds to cover the mistakes, but is can be so done to allow further continuing of the desired rendering...
I have to repeat - at least on Stonehenge paper - as this does not apply with illustration board [at least the ones I've used do not have that same 'whiteness' as it seems the Stonehenge has] - tho again, if the rendering is full cover, and the blooped spot is to be covered, as was in this cup instance, then it still might work [one could only try and see]...

However, there is a craveat to this - laying on the white ink is not to say laying on a white bloop to cover - that would only make for another bloop, and the whiteness would as such indeed be greater than Stonehenge paper white... what is needed, then is, as mentioned, to judiciously lay in the white - that is, to use a small amount and spread it to covering, so it all is soaked in, not laying on top like a plastic shell... that way, too, as each round it done, one can see when to stop, when the amount is just enough to cover and no more...