from the past 11 years of me breeding Miniature Horses, my horses had always started to get toothbumps at around 2 years and up to 3 years (infact my show gelding Rowdy has them now) and i have never had a problem, they are nothing to worry about and they do go away in time, by all means get the vet out to check them, but its not really necessary, if they look too big then i would consider the vet, but to me, toothbumps that are the natural ugliness that all of them have to go through lol