It is not unusual, particularly in teenagers,to get a lump under the nipple or areola which is mostly due to hormonal fluctuations.I don't think that you should be worried too much about it, because usually these lumps tend to get better on their own providing that the area around the nipple doesn't look red and swollen which could indicate infection..
Your daughter's body is changing and hormones play a big role during puberty.Actually, amongst teen girls, the most widespread type of breast lumps and inverted nipples are typically connected to normal breast development and growth.Sometimes the nipples may invert but they will spontaneously erect after puberty is completed, or later after childbirth and breastfeeding.
I am glad you scheduled an appointment for your daughter to see a physician to get herself evaluated clinically.To have peace of mind it's always better to have a Doctor's opinion and guidance regarding our health and the health of our loved ones.
Wishing you all the best to both you ...
P.S.I don't think that waiting till next week to see the doctor is too long to wait.