Soreness after fingering my girlfriend

i fingered my girlfriend a few days ago and it wasnt our first time and it didnt hurt and she was quite satisfied but now its been 3 days. she just told me that she was very sore yesterday but not as sore today. she says it also hurts when she pees but its not a burning or itching pain but the same soreness. there is no discharge or bleeding so we think its doubtful that its an infection or cut but i was wondering if anyone else has had this type of problem. Also her period should be soon and i was wondering if that could have something to do with it.

p.s. i have tried to convince her tolet me take her to the doctor but she is stubborn and wont let me so if you have any info then a solution not involving a doctors visit would be amazing. otherwise ill have to convince her tolet me take her.