Thanks for the query.
You might have developed a post inflammatory hyper pigmentation.
The products mentioned by you are skin lightening agents,
You can use any of these.
Dont worry the dark spots will go.
Please meet a dermatologist
for exact diagnosis.
Swelling in legs is unrelated to this.
Get your cardiac check up done.
Let me know if you have any other doubt.
you can ask a direct question to me on this forum, following the below link.
Wishing you a good health.