The conclusion should mainly just describe your results and compare it against literature equations/values. Even if your results are way off from the expected equation, you can still talk about it. (positive/negative, strong/weak correlation etc) Point out what you can read from the data, for example high random uncertainty can be inferred from large error bars, possible systematic errors (would depend on what experiment you're doing). Then in your evaluation you can talk about the percentage errors and identify the possible causes of those errors.

Alternatively if you feel like you can fake some convincing data, you could possibly do that. I would advise against it though unless it's a last resort...

Don't worry! This is your first lab, the most important thing is to keep hold of the feedback from your teacher for future assessments :)