a lot of red spots suddenly appeared on my both legs and they start to get worse

[HAM1DR3ZA]

hello everyone, 2 days a go i went outside to feed a homeless dog near our house and where i went there was a lot of  thistle and thorn plants there, so i just gone there and returned home after 5 minutes and i felt itchy on my both legs and when i looked at them there were a lot of unusual red spots on my legs which i had never seen before!

i went to doctor and he told me that i might have gone near an insect's nest and i got bitten by a lot of them(though i don't remember such thing) before i got to doctor i went to pool and swam in hot water and i think it made things worse. the doctor gave me pus dryer and an ointment to put on the spots.

since then the red dots are getting bigger and their red color has turned into purple and i have so much pain when i try to walk but when i sit i feel okay.

so i just thought i seek help here to see if anybody had a similar experience or knows about this.

here are the pictures:

https://s31.postimg.org/e8wljorzf/photo_2016_07_18_16_43_23.jpg

https://s32.postimg.org/l1srxu839/photo_2016_07_18_16_43_26.jpg

https://s32.postimg.org/kxg0gu3yd/photo_2016_07_18_16_43_30.jpg