Allergic to pads?

After I had my little girl and got the bc implant I've had weird periods and just dont know if I should go in because doctors aren't really my thing (they always brush off my problems because they think I'm young and emotional)

Tampons hurt all the time now so I don't wear them even though they're my go to so I've been wearing pads and the last couple times I'll get a rash that scans over. This last one got so bad it hurts to wipe and I'm not sure if I'm doing something wrong because my mom wasn't in the picture a lot to teach me or give me advice and I'm also curious if the cup is a decent option?

Opinions?