:wave:
Rabbits teeth grow constantly and they normally keep them worn down evenly through grazing on long fibre like hay and grass, which they chew in a side-to-side action. Sometimes, if a bun doesn't eat enough hay/grass or has a face shape that means their teeth do not meet properly, the teeth can grow unevenly as the rabbit can't or doesn't rub the surfaces flat. This can result in little spikes (also called spurs) forming on parts of the teeth. Some rabbits cope amazingly well with small spikes and can wear them off themselves if they are caught early enough and the rabbit is given plenty of hay to munch, while some rabbits will stop eating, slow down or be in pain at just the slightest spike. Some vets prefer to treat it early, other vets prefer to leave it and see if the bun wears them off themselves.
As you have noticed that your bun is a slow eater it sounds as if your bun isn't going to be able to wear them down himself. I would therefore advise that you have him checked and booked in to have a full dental. By this I don't just mean getting the spikes clipped off, but having them properly reshaped. Once this is done properly, your bun stands a much better chance of keeping the spikes at bay as he will be able to chew normally once the spikes are gone. It is really important that you encourage him to eat lots of hay and/or grass with limited amounts of dried food, to try and minimise the risk of it recurring. Some rabbits are more prone to it than others (especially lops and dwarves because of their face shape) but even so with a few tweaks in diet you will hopefully be able to either prevent it from recurring or at least slow its recurrence down.
Good luck