One year with lice

Hi. I have a one year old and a week ago I found lice egg (nit) on her head. Probably 10 of them or more. Non of them pop. I didn’t see the lice it self. This week I found more of nits some of them popped. What I don’t understand is I don’t know where she got them from. She doesn’t go anywhere. I don’t have lice and my husband doesn’t has it either. Believe me. We checked each other’s head several times. We didn’t find anything. Just her’s. Is there any other way to get rid of her lice other then shaving her hair?? We don’t want to shave it but will do if we really need to. Thanks in advance.