Update: I visited the urology specialist today at Bangkok Hospital, Pattaya. Tests indicated that I still had bacteria in my pee, (possibly from the bacterial bronchitus that I had a few weeks ago or from a UTI or prostitis, even though I have no symptoms of prostatis, other than my usual BPH symptoms).
Anyway, that bacteria will definitely cause an increase in PSA. So I've been prescribed antibiotics to sort out the bacteria infection, and then another PSA test will be performed.
Additionally, the DRE test that the doctor performed was encouraging. An enlarged prostate for sure, but a rubbery texture and no hardness. But even if/when the new PSA is lower (my typical PSA value for the past 8 years has been around 6, with no change), I think it would be prudent to have a biopsy or MRI etc to check that nothing is amiss. My medical insurance will cover any necessary outpatient and inpatient tests and treatment for prostate cancer (I checked the policy!).