Has Dysport made me seriously ill?

It is unlikely that your symptoms are related to your Dysport treatment.  Serious reactions are very rare, but would typically occur within 24 hours of treatment.  I hope you feel better soon!

I don't think your problem is related to Dysport. It is most likely Covid and I would get checked for that. My experience with Dysport is that side effects are very rare and limited to a day or 2. Side effects are also dose related and doses for cosmetic Dysport are very low compared to the 100s of units used for muscle spasms.

I'm sorry to hear you're not feeling well. The side effects of Dysport® are typically mild and limited to redness at the injection site and occasional headaches, though there are other, more rare side effects as well. I'm glad you sought treatment for your flu-like symptoms. If your symptoms continue, you should continue to seek medical attention. It may be a good idea to reach out to your Dysport provider to see if they have any insight into how you're feeling or any specific side effects they have noticed in their clients.