Your dog is obviously distressed about something and this is one of those instances where you have absolutely no choice but to take her to see a vet. Eating grass is something that dogs do quite regularly, even when they are well because it helps with their digestion (even though it can also make them vomit) but the rest of the things that you describe are very definitely signs that she is unwell.
Besides the symptoms that she is displaying, the fact that she also ate a plastic bag is worrying because plastic cannot be digested and could cause a blockage making whatever it is that is bothering her even worse.
Sudden panting and licking her lips could be indicative of a number of things including eating something that is poisonous so if you hang around to see if she gets any better she may actually get a lot worse.
She may have been stung in her mouth if she has picked up a wasp or a bee, which ordinarily would probably not cause too much damage if the sting was anywhere else, but it could cause swelling that prevents her breathing, or she could be having an allergic reaction to it that could be dangerous.
There are too many things that could be the problem with your dog and it is impossible to make a diagnosis on a website; you really do need to stop hanging round and get her to the vet as soon as you can so that she can get a diagnosis and the treatment that she needs.
Besides the symptoms that she is displaying, the fact that she also ate a plastic bag is worrying because plastic cannot be digested and could cause a blockage making whatever it is that is bothering her even worse.
Sudden panting and licking her lips could be indicative of a number of things including eating something that is poisonous so if you hang around to see if she gets any better she may actually get a lot worse.
She may have been stung in her mouth if she has picked up a wasp or a bee, which ordinarily would probably not cause too much damage if the sting was anywhere else, but it could cause swelling that prevents her breathing, or she could be having an allergic reaction to it that could be dangerous.
There are too many things that could be the problem with your dog and it is impossible to make a diagnosis on a website; you really do need to stop hanging round and get her to the vet as soon as you can so that she can get a diagnosis and the treatment that she needs.