The symptoms that you are describing four years after the injections cannot be related to the injections. Neither of these injections can last that long. It appears from the photo that you have a great deal of photo damaging and wrinkles. I would consult a dermatologist about treatment for these wrinkles which could be chemical peels, Fraxel, or micro needling. Best, Dr. Green
Juvederm and botox injections do not cause any long term changes to the lips. Looking at the photos, there is a noticeable increase in laxity, wrinkling and dehydration of the lips. Premature aging can occur from excessive sun exposure, more nutrition, and most of all smoking. It is important to have a good skin regimen and healthy lifestyle to maintain your skin. Seek out an expert in facial injectables and skin aging to discuss options for fillers, botox and likely some resurfacing procedures.
The issues you are seeing are typical of age related changes and have nothing to do with your prior injections. All those products are fully metabolized by now. I think that Restylane Silk is a great product for you. See link.
You can rest assured that anything you see in your lips today has nothing to do with Juvederm or botox injected 4 years ago. These are your lips and you need to address whatever issue you see with a fresh approach. From your picture, I think you would be an excellent candidate for Restylane Silk which was not available 4 years ago. Hope this helps-good luck.
The evolution of changes suggests that the late effect is not related to technique as the collagen should have been metabolized by now and the Botox effect is long gone. It may be that it is the product itslef, Cosmoplast, but this is unlikely as well.