Unfortunately, topical skincare products can have only a limited effect re firming the jawline, and they can't do anything against double chin :(, it is in the plastic surgery area if you are looking for radical results.
Still, of course, skincare can help a little, especially with the overall skin elasticity, improving and preventing further wrinkles. For this, the number one product is a daily broad spectrum sunscreen. Then, I would recommend looking into retinoids. These are vitamin A derivatives that help skin cells behave "younger". You could try our routine builder tool - it recommends you a couple of products for each step in your skincare routine, and you can select from the suggestions based on your budget and preferences. Here is the link: https://whatsinmyjar.com/skincare-routine-builder