Go for it, completely safe. Benzos are safe in terms of overdose (and at least you haven't mentioned alcohol or opioids or anything) and 2mg of lorazepam on top of that isn't all that massive of a dose. Equivalence-wise you'd go up to 130mg temazepam, although lorazepam acts slightly differently and its effects would probably amount to more than 130mg temazepam. Either way, I'd say go for it, if the 90mg seems to not be cutting it. The worst thing that'll happen is you'll fall asleep and/or forget everything.