Your flash can be used to fully cure. Times vary depending on the wattage of your flash. Generally, I place the garment 2 inches under the unit and flash for 45 seconds.
Be careful with doing this on your press platen. It will warp over time. It's OK (and necessary) to flash between colors on your platen, but remove the garment and place it somewhere else to cure. A metal or heat resistant surface works best. In a pinch I have used an ironing board

.