Having contracted Lymes over a year ago, I can speak with a little bit of knowledge. All Tick bites should be kept a check on. However it does not always mean you will go onto to get Lymes.
I did not get the classic big round red ring round the bite area. This does not always occur. If you start to feel feverish, and ache within a week or two get yourself to the doctors. From the picture it does not appear to be an infected bite, but if the red area continues to grow and expand outwards go straight to the doctors. The blood test looks for antibodies in your blood and I believe there are only 4 places within the UK that can test for Lymes.
If you are in any doubt go to your doctor, Lymes if not treated can be fatal, and will cause irreversible damage over a period of time if not diagnosed.
ATB
Sikamalc