If you can touch the LEDs without hurting your finger (about 45 ~ 50C) you are OK.
(IR thermometer is better 
)
Max junction temperature is usually 110C for those parts. Thermal resistance is 7.5C/W.
I don’t know at what temp. they start to derate the lifespan but that’s usually around 85C.
Hope that helps.
Cheers
G