Welcome to JA. I am an Emergency Physician and has 25 years experience. Quickle let me explain the pathophysiology of why shingles wil not be a consideration and neither would I think of Cancer.
It is a spot!, Shingles affect dermatomes (areas supplied by a nerve, like an area supplied by a cell phone tower). So it is unlikely. Secondly, shingle start as a group of 'vescicles' like fine water bumps in very red surrounding and then gradally become red and painful.
Next, it cannot be cancer which often start with a non painful lesion and slowly progress.
Insect bite start with the insect penetrating the skin at variable lengths depending on which insect, and then they deposit a fluid or 'venom'. The pain and sting is the response of your body to the venom, because your body 'reacts' to it and elicits an inflammation which causes the redness and swelling.
The size and severity depends on both the type of venom, the amount of venom and how sensitive your immune system is to it.
The overall 'objective' of your immune system is to localize the venom neutralize it, and if it cannot 'wrap' it up so that it does not spread. ALSO the mouth of the insect carry bacteria, and these are mostly uncommon types.
So the first phase of the lesion was the infection and immune response, the second phase of the lesion is the 'wrapped, destroyed venom and dead bacteria in the middle'. It will keep remodeling over a period as your body 'heals' it
It is now caseated in a fibrous casing and the body will over a period remodel that area of your skin.
The Only concern I have with botox at this stage is the 'unknown factor' of how the toxin will affect the fibrosis that is still ongoing in the wound, So I will advise you to wait. I will advise about 3 full months of wait.
Thanks for making it JA.
If you have any clarifications let me know, otherwise feel free to rate my answer and accept