Sandfly Infestation

In the last few weeks, I keep getting bitten by sandflies.  I have been cycling on the PCN for years now.  Sandflies are very tiny and their bites cause angry rashes and itches incessantly for at least a week.  Then scars are terrible unlike mosquitoes bites which will disappear after a few days.  I have an example fresh bite which was yesterday and one that is a few weeks old.  Applying iodine does not work!