Hi thanks for your question.
The lumps on your inner thigh which comes and goes filled with blood and giving you pain most probably could be boils
(infection of hair follicles) .The other possibilty could be small abrasions which you might be getting from tight under garments with super added infection.I would suggest you to consult a physician who may be able to examine you and let you know what exactly these lumps are?Accordingly he/she may prescribe you drugs.
You may need a course of antibiotics.
Hope this answers your question