Will the horse be to sore to compete? Please help!?

Providing the farrier is good at what he or she does, this shouldn't be a problem. It is common for horses to become a bit tender-footed after getting shoes, but I've never known it to last more than a day. Of course it depends what experience the horse has had with shoes, but the horse will probably be fine. After saying that, be sure that the horse is sound before you take it to the show to avoid further injury.