Vickie, don`t listen to anyone who tells you to roll your flute in or out, they are dead wrong.
play a lower note that you are comfortable with and practice descending long tones, you will find your low C in time, Also, make sure the pads are sealing properly on your foot joint

A dent will not affect ease of getting low C, unless it has cause the tone hole to distort to such a state that it is no longer level, or has cause a post (that supports the mechanism) to be displaced. Both of these are extremely unlikely.

Dents in flutes are VERY easy to get out. I suggest you keep well away from that technician!

ANY leak, ANYwhere up the flute, ESPECIALLY further up the flute, will have a dramatic effect on the ease of getting low C.

The first thing to do is get your flute checked by a GOOD technician, or even a really experienced player or teacher (of FLUTE!). Such a player can quickly determine whether the problem is the flute or your.

M go back and read what he wrote.

"dent on my footjoint right next to the hole of the last key."

RIGHT NEXT TO THE HOLE.
There you go, there is your answer. The pad isn`t going to seal if the whole is mis shaped.

Open your throat as wide as you can and use a lot of support. It needs to be so wide that you can sing and play into the flute at the same time.

As for emboucher issues, finger the low C and roll the head joint out about 90° and blow into the side of the lip plate. If you hear a C, then your emboucher is fine.

A dent near a tonehole affecting pad seal will be much cheaper to take it somewhere to be repaired.

You will need mandrels, dent balls, leveling tool, leaklight or feeler guage, and some knowhow on not destroying tonehole when using all these things.

Yes, Defenestrated we know how knowledgeable you are on repairs. (Laughs!)

Well said, defenstration, in spite of what you said re the piccolo..

PIco, as I said, it is very, very rare for a dent in a flute, near a tone hole, to affect the tone hole. The dent would have to be right at the base of the tone hole, in a location where the tone hole wall is very low. It is possible, but very unlikely. It is pretty difficult to access this area with somthing that would dent the flute.

Now saxophone... that is a different story.

I guess I learned it is better to answer questions than ask them. People will think you are better at what you do if never admit to needing information.

Make sure that none of the keys at the end are dented. That can cause it not to sound right.