What Do You Do When You Add Too Much Vegetable Oil In Cupcakes?

I'm afraid when it comes to cakes they will flop, and you will have to start over. if you try to compensate and add more flour, it will be difficult to get the proportion of the ingredients right, so you could land up with either crunchy hard biscuit like things, or sloppy greasy forms, that do not rise and are heavy.
The best thing to do is start again and measure with cup measures, or measuring spoons.
A general rule is that the amount of sugar and fat (butter or oil), are equal to each other.Too much sugar = crunchy and hard. Too much oil = greasy and not risen.