a locksmith opened the passenger cabin and tripped the alarm doing so. The trunk switch now is not opening the trunk, due to, l think the alarm. Any suggestions?

Do you have a ski port in the rear seat? l find it hard to believe to do not have any spare keys.

Now that the cabin is open, remove the upper portion of the rear seat to gain access to the trunk.
If you had a locksmith there, and the keys were in the trunk, why did not you have him open the trunk.
You're a moron, and so is the locksmith.

call the taxi for a slim jim, AAA or your insurance company has road side assistance, 24 hours locksmith, find your emergency spare key,
or go to the dealership(ask a friend/family for a ride) write down your vin number for them to make another key and take money with you

Do you have an extra remote handy? Call the Lexus dealership and find out what can be done. l hate when that happens!

chainsaw/jaws of life/dinamite..

Is the trunk opened with a lever or a button? You might of hit the valet trunk lock-out switch on accident. The switch is usually in the glove compartment.