It might not go away very fast.
I am chemically sensitive and have to age all my masks for a month or more before use. I don't know your particular mask, but I do 24 hour soaks in either a vinegar or baking soda solution (depends on my mood), followed by airing for a week then another 24 hour soak and then weeks of airing. Even with this the Optilife was totally toxic even months later; it was the most toxic mask I tried.
For now you deal with it and if you can't tolerate it then ask for a different mask at the DME. You might ask them what are their old obsolete masks as they might be less toxic. You might have to ask for a customer "demo" mask as it might have been out airing for months and thus outgassed.
Another thing that might help is running the machine with the mask and use some kind of stuffed animal or pillow so there is some resistance for the flow. I did this before I started on cpap. The mask wasn't the only toxic issue for me as the hose and the fine particle filters on the Remstar's are also toxic for me.
Once you do find a mask you like, I suggest you consider always having a back up one that is properly aged. I do this for my masks and my hose.