Common sense and finances must be considered. As an 'OAP' living on a reasonable but carefully managed budget, I would go with the cost factor. For me, whatever is most cost-effective makes the most sense.
The KISS Principle has served me best in all things photographic. May I suggest, based on budget and the availability of good (= not ridiculously expensive) expert camera repair/service in your area, the following -
1. Have the camera repaired - falls can jar or even dislocate the sensor in D cameras or to a somewhat lesser extent the film plane in F cameras, causing in out-of-focus images (F, D) or scratches (F), often just enough so you won't notice until later when you want to make prints, at which time the consequences of the drop/fall will reveal themselves - or buy another, whichever is most cost-effective.
2. Have the lens repaired, again if cost-effective. For cheaper/older cameras, this probably won't be. Expensive cameras, yes. One of my D700s is currently in for servicing for (among other minor problems) a slightly dislodged sensor. Not cheap, but as this Nikon is no longer made, finding a good D700 on the used market at the present time is just too difficult for me. Mine has 35,000 exposures and is good for many more years of use, so worth the cost. My backup D700 has 135,000 and while it's still a good shooter, won't get serviced if it karks (Aussie slang for "passes away") as it isn't worth investing any more in. Ditto our still-reliable D90 which has about 22,000 clicks on it and seems destined for a long life as the family P&S. So the gearheads gawk when we use our cameras, but I reckon our results are far better than theirs...
3. Buy another lens,new or secondhand, again whichever is cheaper. From a reliable seller. These days, Ebay with its oversupply of expensive crap everything, is last on my list of such.
Home-repairing cameras can be dangerous as they are (usually) highly-engineered and complex machines. I will never buy a camera secondhand if it shows even the slightest evidence of tinkering by previous owner/s. Lens repair is easier but only for simple fixes. Misaligned cameras and lenses mean big trouble!
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