My son(2-yr old) knocked his front tooth 3 months ago, the tooth was bit loose for a couple of weeks. Now the tooth looks normal and he eats normally, but he got a small blister on the gum right on that teeth. The blister doesn't hurt and he eats normally. The blister is in white color. Could the infection be treated other than by pulling out the tooth? We really do not want him lose his teeth so early!