INC from JustAnswer UKLaw wrote:
It is illegal to buy prescription-only drugs without a prescription or consultation in the UK, whether on or offline. This law currently does not apply to websites based abroad as long as you're buying for personal use. The same rule applies if you were to bring them through airport customs here.
There is currently a loophole in UK in the Medicines Act 1968 which means that although many drugs can be dispensed only after a patient has consulted a doctor, the consultation need not be face-to-face. Therefore quick online consultations with net doctors make such dodgy transactions legal.
Therefore, in response to your question, it is legal to import non-prescription drugs provided you are not selling them on without the appropriate licences.
I think this is typically legalistic gobbledegook for:
for personal use, it is legal to import (from an overseas website or in person by air) what the UK would consider 'prescription-only' medicine even when not actually prescribed.
So unless you were planning at the time of re-entry to flog them on, the answers to your questions are: NO, NO and NO respectively (rest easy!).
I forgot to mention that the date of the quote above is showing as 7 years ago. That is a bit alarming given There is currently a loophole in UK in the Medicines Act 1968 ie even at that time some grounds for expecting a change in the legislation. However if changed only to close the loohpole then only face to face consultations may have been affected.
The 1968 Act appears still current.
Note also:
Possession of a prescription only drug without a prescription is only an offence if the drug is also controlled under the Misuse of Drugs Act 1971 and possession is thus specified as an offence. Therefore, for example, possession of a prescription only antibiotic without a prescription is not an offence.
Whatever the medicine, if OTC in USA it is not at all likely to be controlled under the 1971 Act.