I'd also suggest a couple of other things that people may have mentioned but perhaps bear repeating:
First, besides looking for an executive branch/White House angle, also contact your members of Congress, both your US House rep and US Senator, and make them aware of this issue and, really, educate them on the silliness and overreaching of these regulations. You will likely find a better atmosphere for challenging bureaucracy-overreaching in the first 100 days of the new Administration when members of Congress are looking for ways to make an impact and show activity. This is true, regardless of political party, but certainly more likely if your rep and senator(s) are Republicans. But now is the time member of Congress are preparing their agendas for the first 100 days, so the sooner the better.
As mentioned above, I'd make three points: 1) that this is FDA/Executive Branch over-reaching as a health matter; 2) this is, as a matter of government philosophy, an excessive delegation to executive branch agency (i.e, one thing many Republicans are particularly upset about is how past Congresses have permitted executive branch agencies to take over what are essentially legislative roles, or at least fill the vacuum of Congressional silence to undertake politically-motivated activity (in this case, putting tobacco blenders out of business), but it has happened in many agencies; and 3) these regulations are a job/business killer. This last argument will be more persuasive to your House rep who has fewer constituents than your senator (unless you live in a really small state). I emphasize this: to the extent you can provide an example of how ludicrous these regs are, eg, the cost small dealers will face or the burden of needing to get pipe tested or whatever. Most of these members are NOT pipe smokers, or smokers at all, probably, so they may not get the "tobacco" part of this; but they'll get the "stupid, costly, regulation" point or the "job killer" part.
Second, if you have favorite tobaconnists, esp those with blends/pipes/etc falling under the regulation, check with them and see if they are active in a trade association that will actively pursue something with Congress in the coming months. If not, you may want to suggest that they look into it, or in the alternative, have them directly contact (as above) their rep and senators.
Also, it may well be that a friendly House member will be a member of a committee member with FDA oversight responsibility. That's a home run, if they are friendly to the cause on one of the three bases I mentioned above. This kind of thing may well be an adjustment added to an FDA oversight/spending bill.
I can't emphasize how important the first 100 days will be. I know these things will take longer than that, but it is really better to be first in line, than last in line.
The suggestions re contacting people in the Administration are good, and I wouldn't say it would never happen, but, in my experience, this is the kind of thing is more likely to happen through one or several friendly representatives, than through a cabinet member pushing it.
Personally, I'm not a big smoker (although I am fine with it and like to have it around), but just the idea of this type of government social engineering and overreaching drives me nuts.
PS: I say that these arguments will be more persuasive to Republicans, which is generally true, but if you come from a tobacco state, say Kentucky, the Democrat congressmen will also likely be quite receptive, too (as you see with Fla. bi partisan proposal re cigars).