You are right, this is not going to be any kind of fun. I don't know if the doc will OK it, but many of us found Aquaphor to be a godsend for this treatment. I can't see why you couldn't put it on your lips. If I could have put Carac on my upper lip I would have, to avoid the Mohs procedure.
The other thing I tried was upping my Omega 3 and 6 intake, drinking a ton of water and eating a modified Atkins diet. Not to lose weight, just to get rid of the refined starches. Lots of fresh fruits and veggies. That sounds really lame I know, but my reaction was manageable. 3 weeks on my face and 5 on my chest. Yuk.
If your doctor doesn't talk to you about temporary disability and pain meds - make sure you bring it up. It's not asking too much of them to have that ready to go, should you need it. I didn't end up using mine, but it was good to know I could if I needed it.