The discussion section is not always about what you found, but what you did not find, and how you deal with that. Stating that the results are inconclusive is the easy way out, and you must always try to pick out something of value.
Using the Discussion Section to Expand Knowledge
You should always put your findings into the context of the previous research that you found during your literature review. Do your results agree or disagree with previous research?
Do the results of the previous research help you to interpret your own findings? If your results are very different, why? Either you have uncovered something new, or you may have made a major flaw with the design of the experiment.
Finally, after saying all of this, you can make a statement about whether the experiment has contributed to knowledge in the field, or not.
Unless you made so many errors that the results are completely unreliable, you will; certainly have learned something. Try not to be too broad in your generalizations to the wider world - it is a small experiment and is unlikely to change the world.
Once writing the discussion section is complete, you can move onto the next stage, wrapping up the paper with a focused conclusion.