Could the side effects such as a feeling of heaviness and swelling after bad Botox be permanent?

Some of your symptoms can be attributed to your Botox injection but Botox side effects are usually gone in a few weeks to a few months. If your symptoms persist you need to see a physician.

It is unlikely that your numbness and blurry vision are related to your Botox injections. You could get bruising, and drooping of your brow and lids that would be temporary. Botox affects the motor nerves, so it should not cause numbness which is related to sensory nerves. Drooping can occur from forehead injections in some patients. Short term itching could occur from inflammation or reaction to a topical anesthetic, but I do not see how that would persist six months later. I would suggest you discuss your issues with the facility where you had the treatment, and consider trying a different physician if you decide to try Botox again.