When she screams and cries, move her away from everyone and let her work it out herself. Completely ignore her until she stops crying and is ready to again join the other people. Let her know that that behavior will not be rewarded with attention. And make sure to give her positive feedback on the things she does right. Praise her for her good behavior and her good choices of toys and activities.
Some babies are slow to get their teeth.
Most likely your baby's tooth will come in in the next few weeks. However, if it does not it would be a good idea to consult your baby's doctor. Now that she is 7 months old, she wakes at approx. She is eating well and drinking plenty of formula. Please hurry, I'm very tired.