Flu like symptoms after cosmetic Botox injection. Any suggestions?

I would say that it is very unlikely that these symptoms are related to a standard Botox injection.  It is more likely that this is a coincidence.  You may be actually getting sick with the flu, so I would follow up with this to a primary care doctor.

Thanks for your question. This is a question that we
get asked often by our patients. The most common SIDE-EFFECTS of toxin
injections include: Swelling, Redness, and Bruising at the site of injection. Complications
are rare and only temporary, but may include paralysis of other nearby
muscles, temporary eyelid ptosis (dropping of eyelids, 2% risk, lasts 2-3
weeks), temporary brow ptosis (dropping of eyebrows, 2% risk, lasts 2-3 weeks),
cross-eyes, ectropion or edema of the lower eyelid, dry eyes, double vision,
transient headaches (10%), local numbness (lasting 2-3 weeks), flu-like
symptoms, rash at the injection site, pain at the injection site, infections,
and bruising (need to avoid blood thinning medications). Cold compresses
may be used immediately after treatment to reduce swelling only if needed. This
may be applied for 3 minutes, 3 times per day, for up to 3 days. This is best
done with a bag of peas in a zip lock bag. Only apply light pressure to the
area. Only take Tylenol if you get a headache or migraine.