I would be careful using hibiscrub near the mouth as I don't think it is supposed to be ingested. For now I would just stick with bathing with warm water and try squeezing any muck out if he'll let you.
I know it's revolting but if you are able to get the scab off this will aid in the healing process as you can get all the gunk and puss out but of course this all depends on whether you have a softie like my Zephyr who will let me do just about anything to him cuz I'm his mummy or whether your lad is a bit more feisty.
A bit more info on Leucillin: The most versatile first aid product available, a revolutionary anti-bacterial, anti-viral and anti-fungal spray, suitable for use on all mammalian animals.
It out-performs all other products killing 99.99999% of germs on contact, whilst remaining pH neutral, non-toxic and will not sting. It provides you with a powerful hypochlorous solution to combat all infections and kills germs instantly by destroying the bacterial cell on contact.
No surviving bacteria means no resistance to healing, demonstrating rapidly reduced recovery time