I've been researching Botox, since my doctor will be giving me injections along with a fissurectomy next week. I'm finding that there are some risks involved that my doctor didn't tell me about. Has anyone had any adverse reactions to Botox such as an allerigic reaction, breathing issues, or Botox reacting to herbal medications? As this surgery gets closer, I'm feeling a bit apprehensive, maybe I'm worried for nothing?

I had Botox and didn't experience any such side effects. We've had lots of folks here get Botox and I don't recall any of them having those severe side effects either. In most cases, the procedure is largely uneventful, and if there is discomfort, it's usually localized.
That having been said, yes it's always possible to have a serious allergic reaction (i.e., anaphylactic shock) to any substance, and Botox is no exception. But it's extremely rare and I wouldn't worry too much about the possibility of an allergy (just my opinion). That risk exists with every single thing you eat or touch every day.
The other thing the literature might be referring to is the isolated cases where Botox travels outside of the local area where it was used. That's an exceedingly rare complication but it's a risk that does exist. Botox is one of the most powerful neurotoxins -- the reason it works is because it totally paralyzes muscles. So if it were to somehow travel outside of the injection area (for example to your muscles that control breathing), then it could have some real nasty effects. This is also exceedingly rare. I'm a pretty hardcore worry wart and I was mildly concerned about this going in, but I knew the risk was so low that I didn't dwell on it much. I figured the odds of being in a fatal car accident en route to the clinic were higher than having Botox spread where it shouldn't
To be perfectly honest with you, I would not worry about the Botox at all. The fissurectomy will likely (almost guaranteed) cause considerably more discomfort in the long run, and IMO the Botox will be a breeze by comparison. (Note though that I've never had a fissurectomy so I'm not speaking from direct experience there.)

I also haven't heard of any side effects, nor experienced any myself. As NG said, the fissurectomy will be the "killer": I had very bad pain after each BM for the first week (to the point I was shaking up to 10 minutes until the painkiller kicked in) and am in moderate pain to this day (5 and a half weeks post-op). So, it doesn't seem like a real/easy fix until now, but stay tuned for the future...

I had Botox two different times and had no allergic-like reactions either time. I maybe had a tiny bit of soreness at the site, but really not anything that I can even recall that much. I chose to take it easy and it was more because of the emotional state I got myself into than the actual event! But like others have said above, I am sure it is possible, as with anything, to have some type of reaction and I am glad to didn't read what all of them were!
Bambi