An oil leak where you see a drip form, but it doesn't drip is not an immediate problem. If this is something you don't want to fix right away, there shouldn't be a huge issue. There are two concerns:
- Keep a close eye on the oil and ensure it stays topped off. You'll want to check it a little more often than you would under normal circumstances so as to avoid running your engine dry accidentally.
- Even though you don't see any drips coming off, be assured you are losing oil. This is not good for the environment and should be avoided. While you may not be able to make the fix right away, plan to do this as soon as possible.
Depending on where the oil pressure sensor is leaking from, you might be able to fix the issue. If it is leaking from around a threaded area, try and use some teflon tape on it and get the leak fixed. If the sensor is cracked or is leaking from somewhere else, it may just need replacement. Very simple fix and for the most part should be cheap.
On the oil pan, you may just see if the oil pan bolts are loose. Try putting a socket on them and see if they will tighten a little. This may stench the flow of the oil. I will caution you not to over tighten them. This would be easy to do. I don't know what torque value they should be, but don't go cranking down on them because you'll more than likely just make the leak worse.