When a bow of a string instrument warps due to misuse, neglect, or some other reason, can one forcefully "unbend" the bow to fix it. If not, what are other ways un-warp the bow other than bringing it to a shop?
Yes, a bow can be re-cambered, but it requires some skill and I wouldn't recommend trying it yourself (edit: unless it is a cheap bow you want to experiment on and don't care if you wreck it).
When the bow is made, the wood of the bow is bent into shape using heat, often by a careful application of flame. The wood is unfinished at this point, so a re-profile usually means a refinish job as well.
When the wood gets hot enough the fibers release and the camber can be added to the profile. There is a delicate balance between the shape of the bow and its balance and bow makers can train for many years before mastering the art.
Depending on the age and value of the bow it can be worth it to have it re-worked. If it is an entry level or student bow, then it is usually cheaper to replace the bow. Prices in the U.S.,from a re-hair to a full rework, range from about $85.00USD to $400.00USD and up.