I did the exact same thing just after Christmas, I was chewing some food and somehow caught my lip and bit down hard on it. I developed a large lump as you have all described that looks like an oversized ulcer.
After 2 weeks I went to my doctor who advised me I had crushed a salivery gland and they very rarely require surgery and will unclog itself given a month or two. He referred me to the dentists as I have a tendancy to worry.
Almost two weeks later it is no better, I went to the dentists today as recommended and my dentist again said it will be fine and to leave it alone. He also said to give it a month or two. He recommended that I suck on oranges or lemons or anything else that will get saliva flowing to unblock the gland.
Both advised it's harmless, rarely requires surgery and will not turn cancerous. Mine thankfully is not painful or anything, merely unsightly.