|It all depends. The rash is an overblown immune system response. For some people, it'll show up in hours for others it may take longer. Someone who has never had a reaction before can take a few days before seeing an initial outbreak.
There are many variables involved here including your own immunity. Not everyone is allergic to urushiol oil.
If it's been a week, it's likely that you won't break out now with a rash.
Hope this helps.