Dermatitis from urushiol irritation can take one to three weeks to heal. The only thing you can do is try to mitigate the swelling and itching somewhat.

[He gets up and goes into his bathroom, returning shortly with a pair of washcloths soaked in cold water. Gently he lays the damp but not dripping cloths over the rashy patches.]

Cold wet compresses for twenty to thirty minutes a few times a day. Let me see if there's calamine lotion or hydrocortisone cream in the first aid kit.

[Back into the bathroom he goes, coming back with a plastic tube of topical medication.]

Sparing application of this over the affected areas twice daily. It might sting more if you've scratched your skin raw, so try not to. If you see any purulent drainage, even a small amount, let me know immediately. This sort of rash can become infected if you're not careful.