Hello, She most likely has a hematoma. This can be from the injection or bruising trauma from biting the tongue. The body will take care of this with time. Healing may involve some tissue changes and even an area of solid feeling tissue can be part of normal healing. You can expect a slow healing process that can take 3 to 6 weeks to totally resorb the hematoma. Warm salt water rinses and anti-inflammatory medication such as ibuprofen may assist healing. If the area increases or does not continue to heal, visit the dentist to evaluate if drainage of the hematoma should be considered. In general, this is not considered an unusual event and you do not need to worry. It is a very positive sign that there has been little pain and little swelling. This indicates healing is progressing well. Thank you for your inquiry. I hope your daughter will continue to feel better.