The dermatitis rash caused by poison sumac is not contagious, but the urushiol oil clings to everything it touches contaminating clothing, tools, or even pets which can carry the irritant to other places on the body or even other people. Every item that may have contacted the poison sumac plant must be washed thoroughly with soap and water to eliminate the oil. Scratching the rash will not spread the poison sumac caused dermatitis to other areas of the body, but it can result in a secondary infection.
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Apparently, it should take about 3 weeks to heal. The cold water you are applying is good. Also to help lessen the itching yu can use calomine lotion.
As you wore gloves, it is likely you got the resin from them when you took them off, or touched something that had resin on it.
See your your doctor anyway, just to make sure the rash is not infected.
Best wishes
I presume you put the gloves on before you started to pull out the weeds?
What type of gloves were they? If they were rubber gloves, then that would have protected you from any poison weeds.
It could be that you are allergice to the rubber gloves. I am. I have to wear latex free gloves to protect my skin when I do gardening.
I would suggest you see a doctor, so that he can recommend the right cream for this as well as an antihistamine. In the meantime keep the area clean and dry.
Best wishes