Please tell me about possible side effects after Botox injection.

Botox itself is a safe formulation and rarely has side effects, but the side effects caused by the relationship of the injection site include eyelid ptosis (eyelid lowering) and eyebrow ptosis.
It occurs with a probability of 1% or less in the treatment of the eyebrows and forehead, but it surely recovers.
Next, symptoms such as headaches, fatigue, and a common cold are rare as those occurring regardless of the injection site.
In rare cases, facial nerve paralysis may occur due to injection into the jaw muscles.

Dr. Kure