My suggestion is not to believe everything you read online.
If your cervix was hanging low and was soft, it's possible the brush took off some of the tissue. This is the kind of thing that happens (except not nearly as severe) when the doctor uses a swab to remove some tissue when doing a pap smear. I think the cervix should recover from this, but it would not be stupid to call your doctor and discuss this with a nurse or with the doc. They might want you to go on an antibiotic to prevent infection of the area (especially if the toothbrush was not sterilized first) and they might want you to come in for an exam.
Goes without saying, don't do this again.