Hi and welcome!
Please respect that we do any moderating/advising unpaid in our own free time. We try to answer all threads in this section in due time and as quickly as we can. This is the weekend, after all.
Please also post your problem in a proper post and not just a link to a blog.
It is important to make sure that the two top teeth are still sitting firmly in the mouth; if not, the tooth root could be affected. Please see a vet if necessary.
Front teeth are self-sharpening, so they should sort themselves out once they meet. Teeth grow very quickly if they are not ground down, so they should grow back in a matter of days. See a vet if the teeth don't grow back evenly and if there is a slant where the front teeth meet.
Until then, you may want to mush up the pellets, cut up hay or syringe feed and grate any veg. You can find more tips at the end of our syringe feeding guide in the section about dental guinea pigs. Weigh your piggy daily at the same time in the feeding cycle instead of weekly; you need to start supportive syringe feeding if the weight loss surpasses 50g/2 oz.
Complete Syringe Feeding Guide
Be aware that mineral stones are not necessary and are in fact ignored by guinea pigs on a good, balanced diet. Additives to water are actually counterproductive; guinea pigs drink noticeably less while you are unable to control the intake. Water also tends to go off and go green much more quickly with additives. If you want to give added vitamin C, it is much better to either give it directly or syringe it dissolved in 1ml of water for optimal efficiency and to make sure that the guinea pig gets the full benefit.
You may find the detailed information in this thread here helpful:
Recommendations For A Balanced General Guinea Pig Diet
PS: I am merging your threads to prevent confusion.