Hi.. Thanks for the query. As per your query first thing that I would like to tell you is that a small pulsating lump on lower lip that is pulsating since 24 hours is not a sign of cancer.. Canacerous lumps are commonly painless and are present since years.. A lump that is present since 24 hours and pulsating is not cancerous, rather it can be an infected gland, bacterial infection, bug bite etc.. So no need to worry about it as it is nothing serious.. Take anti inflammatory painkiller like Ibuprofen or advil and do cool compresses over it.. You can also apply steroid ointment like Triamcinolone Acetonide along with numbing gel to relieve pulsation and pain.. Hope this helps.. Regards.