Scars shouldn't really afffect shedding I wouldn't think. My girl has a good sized scar on her underside from an old accident and never has a problem with shed. Soaking gets rid of the snakes natural oils and usually makes it harder for them to shed. I would just have a water bowl big enough for your snake to soak if it feels neccessary. Are you raising the humidity up to 70% while your bp is in shed?
Plus to add forced soaking can be very stressful for your snake. Your bp isn't swimming its trying to get out. I only clean my snake when she gets soiled and that's just a wipe down not a bath.