The time it takes for lead poisoning to kill you depends on the amount of lead poisoning you have and whether you ingested a lot or a little.
Most times the lead poisoning just leads to kidney failure which then kills you overtime so it may take months to years for the lead poisoning to actually kill you.
If you think you've been poisoned by lead or have ingested lead then you need to go to the emergency room or urgent care to get treated for the lead poisoning.
Because if you do not get treated for the lead poisoning it can lead to eventual death which can be months or even a few weeks after ingesting or being poisoned by it depending on how much lead poisoning you have.