I believe, you have to provide much more details, to help us find an interpretation for your observation.
1. What is the sample you are investigating? What did you do on your sample? With respect to what property do you see a red or blue-shift? To literature? With respect to before doing some change to your sample?
2. Which method are you using/ which property are you investigating? Phonons/Vibrations/Plasmon/Polaritons with Raman/(FT)IR? Electronic transitions with some form of UV/Vis spectroscopy? Deeper electronic levels with some form of deep UV/X-Ray spectroscopy?
Based on that, maybe, the collective mind can give you some hints, what an interpretation could be, what the caveats and limitations of said interpretation is, what further things you may could do to confirm or dismiss an interpretation.