Thank you for your query on Healthcare Magic.
For injury on lip, you can apply a gel containing metronidazole
thrice daily and for pain you can apply local anesthetic
gel which contain benzocaine
Give plenty of oral liquids and very soft diet
The black spot is due to the clotted blood.
Nothing to worry as the mucosal lesions will heal fast.
Consult the doctor for physical examination and for prescription of medication.
Hope I have answered your query.