Hi Liam Skye,
It may be from the Decadron infusion, Dexamethasone, a corticosteroid, also under other names, given to reduce nausea side effects with cisplatin and others. To counter this effect, Thorazine or similar is given, Gabapentin or changing the corticosteroid. Sometimes its from Cisplatin, and may reduce the dosage or from other causes. Let your medical team know.
Good luck.