How to cure mouth sores on Guinea Pigs?

HISTORY
A few months after having my Guinea Pig, he started to develop this weird mouth sore. I have tried many different things that people posted in the internet. I found that all of them helped but, didn't work completely.

We went on vacations and a friend was taking care of my Guinea Pig. When we came back, I found my pet with mouth sores, they were so big and thick. At first, I thought to treat it myself and if it went worse in a coulple of days, I had definitely had to go to the vet. The thing of these irritations is that it didn't seem to bother him; he still ate and behaved fine. So it doesn't make you feel to go as soon as possible to the vet. (do you feel the same?)

It has been a long month process of research and constant attention. Finally, I have found a few tips that will help people with this problem.

This is what I did:

1.    STOP feeding him with fruits, especially apples.

Everywhere says to give them good amounts of vitamin C, I found that acid fruits (any type of berries, oranges, apples, grapes, etc) trigger this mouth sores. Limit the fresh food to veggies. I also try to give him ones with less amount of water, like carrots, broccoli and peppers.

2.    Try to feed him with fresh Dandle Lions flowers. Wash them thoroughly.

It is widely used in humans to help with inflammations. I found that every time I gave him a few of those, his sores were healing faster.

3.    Get dry food and hay that has plenty of vitamin C, since his diet is limited at this time. Watch-out for the water supply, because he is going to be thirstier.

4.    Wash his mouth with warm water to soften the scabs. Carefully try to swipe-off any loose scab. (DO NOT PULL THEM)

5.    Apply triple antibiotic cream to the mouth sores, 3 times a day for a week. I used a k-tip to apply it as close as possible to the skin. I use a generic brand.

6.    After a week if you see that it is better but not fully clear, apply antifungal cream to the mouth sores, 3 times a day for another week. I use clotrimazole 1%

I had done this for 1 month now and it seems that going back-and-forward from antibiotic to antifungal cream makes a big difference.

As far as food goes, I am keeping him away from fruits and he is doing fine. I have been more open to other types of veggies and he is doing fine. Although, he is 99% heal, I am waiting him to be completely clear of the sores for another month, so I can treat him with a strawberry.