"If I start, I have to keep doing it. Won't it make things worse?" The quick answer is no, it wont make things worse.
If you are going to a qualified medical professional that has experience . If the treatment is done safely with approved product then you are quite literally pushing "pause" in the aging process. Many times you actually push rewind.
Let me start by explaining the cause of a dynamic crease or wrinkle. An example of this would be the "number 11's" between the eyebrows/glabella or the lines at the side of the eyes/crows feet. When the muscle contracts because the sun is shining, or when you cant understand why your child or spouse just did what they did; The skin that sits on top of the contracted muscle gets folded and wrinkled. If you contract that muscle repeatedly throughout the day, then a line starts to form from that little fold in the skin. Botox or a neuromodulator can be injected directly into the muscle, which renders the muscle relaxed. The folding stops and the skin is able to sit flat and smooth.
While the skin is smooth and flat, you're allowing the skin to replace itself in an undisrupted manner. Which helps the skin's texture. This is why people who are consistent with injectables sometimes appear to be looking younger and younger. For some people who's lines have developed into creases, it may take 3 or 4 consistent treatments to lessen that crease but, normally they see a great improvement.
If you decide to stop treatment, the muscle recovers and movement starts up again. This normally takes 3 to 4 months after treatment. The little skin fold will start to show and most times it is better than when you started.