Just the usual suggestions, dust it out. Also 90 C is on the hot side but it's still not overheating or throttling down, so I would not worry too much about it. If you are an advanced user you will get a few degrees off with a little undervolting but I would not recommand it to anyone who has no experience with such things. Blowing out the dust is your best bet.
Laptop: G751JL
Processor: i7-4750HQ
Graphics Card: GTX 965M
Memory: 8 GB Samsung (stock)
Storage #1: Samsung 850 EVO 250gb
Storage #2: 1 TB 7200 rpm (stock)
OS: Windows 10 x64