The answers to these two questions are: "Probably not" and "Probably"
First, 'will it hurt'? Smokers always accumulate residue inside. But, this is usually the expected oil, grease and smoke produced form normal use. This accumulation usually enhances flavor, not hurt it. But, when they get a layer of cresote, in all honesty, it should be removed. Probably as much for your own peace of mind as for any actual affect on the Smoker. I doubt if the functionality is going to be altered much, due it's presence. And, unless it is exceptionally thick or exceptionally smelly, it is doubtful that the presence of cresote will taint or contaminate future smokes. However, if the odor is bothersome when you open the door, it may be strong enough to have some influence. At least for a while, until it dissipates. In this case, you should remove as much as possible, without killing yourself in the process. Odor from most everything dissipates over time. This will too. In addition, it will soon get covered by the more normal residue, as mentioned before, which will lower the odor and help shield it from future smokes.
Secondly, 'is there something else I can do'? Scraping and wire brushing, as mentioned by several others, is the common practice. I did try an additional approach, when it happened to me. I removed all the moving parts(racks, pans thermometers, etc. I got the smoker nice and hot, as you did. I used the putty knife to scrape as much off as possible. I wire brushed after that. Then, I fired up my old Power Washer and had a go. I found that I was able to blast off most of what remained. When done, it was pretty nice looking. Then I fired it up again for a few minutes to dry it out. I did go to the extra effort of spraying with a PAM like spray and re-curing the smoker.
After this process it was 'good to go'. If you have a PW, or can borrow one, you might give this a shot. Hope this helps.
Good luck and let us know how it goes.
Skip