If you will see a leak in your pipe, then worrying about it is a normal thing and taking a plumber help is the best thing that you can do. But before, we suggest you to do following few things so this leak in your pipe cannot do any further damage to you.
Stop main electricity and water supply: Continuous leaking of water supply with fast pressure can damage your house and pipeline, both and it can increase the problem as well.So, when you see any leakage make sure you turn off the main water supply for some time until you get a plumber in your house. Also, if possible stop electricity supply as well, so you do not remain vulnerable to any electricity accidents.
Empty your pipes: After you turn off the main water supply and electricity, you will have less worries about the water damage, but pipes might have some extra water in it that might leak continuously and can create a problem for you. So, if possible just turn on all the water taps, flush the toilets and empty your water pipes.
Close it with a duct tape: If you see the water is still leaking or you cannot turn off the main water supply or empty pipes, then close the leaking or hole with a duct tape.Add several layers of the tape on your pipe for stopping the leakage. This duct tape will not hold it for a longer time and it might not stop all the leaking either, but it can give you enough time to get a plumber for its repairing.
So, if you see any leak in your pipe, make sure you are not panicking about it, just calm down yourself and do these things to save you properly.