Ingrowing toenails, contrary to popular belief, do not grow sideways. They also do not grow diagonally. The reason that a nail will ingrow is because there is either too much width of the nail compared to the amount of space available, the nail has been cut back too far and a sharp edge has been left, or the nail is very curved and sits under the level of the skin.
If you have a single episode of an ingrowing toenail that is only very slight, then you may be able to get away with just having the edge trimmed out.
This being said, a lot of ingrowing toenails tend to be a repetitive issue and will only continue to return. In these circumstances, it is possible to have the nail edge removed with a local anaesthetic to freeze the toe, and after this we can use a chemical on that part of the nail to make sure that it does not grow back.
If you attend and I suggest this, it is likely that I think this will continue to be an issue, and so I would say that you should definitely ask me why I think it would be, so that you can better understand your options.
An ingrowing toenail is the result of part of or the whole of the edge of a nail pressing into the skin and breaking the protective barrier that keeps germs out.