From the small amount of info given so far, I'm afraid the odds of repair are probably not good. But that is based on some guesswork.
Voltage regulators rarely fail. When you have less than 3.3V from the 3.3V regulator, the cause is almost always something else has failed and is drawing too much current. The voltage regulator has safety features to limit its current and maximum temperature by automatically reducing the output when the load is too much. When you see less than the correct voltage, typically it's because the regulator is working properly and those safety features are coming into play.
However, one well known situation where you get not enough voltage output is when you have not enough voltage input. Normally this happens when the power source is a nearly dead battery or an unpowered USB hub. You can pretty easily check by just measuring the VUSB or VIN voltage. If it's something like only 1.9 volts, then of course you'd expect the regulator to only be able to output 1.6 volts.
But if you have a solid 5 volts input and the regulator is only giving 1.6 volts output, and especially if it's running really hot, that's a sure sign something is drawing too much current.
If you get lucky, that "something" might be a circuit you can disconnect and troubleshoot. If you're unlucky, it's quite possible the main processor is damaged.
Which of these scenarios applies to your situation, I can not know. Rather than a lot of back-and-forth questions, hopefully this longer explanation which tries to cover most cases helps.
