Devastated our dog lunged at our 8 year old-long post

I need serious non-biased advice. Thank you for your help in advance.

Last night we were sitting in the living room and our 8 year old daughter began gently rubbing our dog with her foot near the stomach area as we have all done many times. Suddenly our dog snapped, lunged, snarled. And showed her teeth to our daughter. Our daughter jumped back and began crying. My husband moved our dog to her dog crate. We have a 10 year old Presa Canario. We realize that she is known as an aggressive breed. We have had her since she was 5 months old. When she was 6 months old we had her in private highly recommended dog behavior training. It was a very positive experience. Our dog has always been loving to our daughter. When she was born, my husband brought home baby items for our dog to sniff before we brought the baby home. We introduced the baby to our dog in a loving manner. She slept at the door of the nursery nightly. She has always been very protective of our daughter and will let her walk her and play with her. We taught our daughter early on to be respectful to the dog and has never hit her or pulled her tail.

Our dog is dog aggressive (she has bitten two dogs) and does not like outsiders. We can only have her around people she met as a pup such as inlaws. She will growl at new people and we have to crate her when we have company. Taking her to the vet is difficult because she doesn't like strangers. We cannot board her so we always take her on vacations.

She eats a raw diet and has been in excellent health.

Part of my fear is that I have a step daughter who was bitten by a different family dog when she was 8. This was ten years ago. We had a Cane Corso who was 2 at the time. He bit my step daughter in the face. It was devastating and we had to put him down. My husband was especially devastated because he is a dog lover. We tried to do things differently this time around but I am very worried that our dog will hurt our daughter. We can't give her to a new home because she doesn't take to strangers. My husband hasn't been able to talk about what happened...he just keeps hugging our daughter and checking on our dog.

Please provide any advice you can. Also to note our dog has been sleeping in her crate at night for the past month because she started having peeing accidents in our bedroom at night.

I'd take the dog to the vet for a health check, any change in behaviour should be investigated and at 10 years old she's getting old, tbh you should have already taken her if she's peeing in the house overnight.

Please take your dog to the vet.

It very much sounds to me because your dog is peeing during the night she could have a UTI which at the least would make her feel uncomfortable and irritable and could account for her sudden change in behaviour.

Vet!!! It sounds like a UTI which is giving her a sore stomach. Your daughter could well have touched on a very sore spot which she naturally reacted to

Vet to get her checked over for any unsoundness. If all clear behaviourist/trained to work with your dog and reassure your daughter that it's ok. Dogs are really sensitive and if she picks up that everyone is panicking around her it might not help.
Presa's are big dogs and though I'm not doubting that she maybe shifted and had a good grumble you've got to make sure your not mistaken and uncomfortable reaction as an act of aggression. She was maybe sleeping he got startled? Maybe her fur got rub a bit wrong and a bit of friction happened? Maybe a UTI as suggested above?

When it's your kids I know you have to put safety first so if it were me I'd go to the vets and take it from there. Talk to your child about what happened and make sure she's not put off and scared stiff. And if you can I'd keep a positive Interaction with the dog so she doesn't feel shunned for something she's problem forgotten and got over in her head already.