My G. Pulchra won't leave the mat.

My G. Pulchra won't leave the mat. He or she is defensive and moody. Normally he/she is very docile and calm but the last couple of days has ben acting like this.
I also saw a small flaky patch on the rump. Could it be premolt.

Could be. Or it could just be comfortable on the mat (I assume you mean a web mat?) and moody because it feels like being moody. Sometimes with my larger tarantulas, I will offer one cricket and if the spider ignores it, kicks hairs at it, or bats at it I'll take the cricket out and assume a molt is imminent. Then I won't offer food for a couple weeks, make sure it has plenty of water, and leave the spider alone and see what happens. Most times, the spider will molt.

It's not a very scientific way of doing things, but it might give you an idea. Good luck!

Thank you for the input. I will just leave he/she alone for a while and see what happens.