Hi.. Thanks for the query.... As per your query white bumps at the corners of the mouth of your daughter can be most commonly due to Herpes Virus Infection causing cold sores and it forms clusters of small fluid filled blisters.. You should consult a Paediatric dentist known as Pedodontist and get her evaluated and if he suspects cold sores he can confirm by getting investigations done like Viral culture and antigen antibody reaction.. If herpes is confirmed antiviral oral and topical application like Acyclovir, valacyclovir, famicyclovir can be advised to reduce the duration of the eruptions. If herpes is not ruled as the cause other causes like Fungal infection can be checked for.. Hope this helps.. Regards..