Commercial fixed wing Flight Attendant reported; while deplaning passengers; lingering fumes and odors caused deteriorating health issue. Flight Attendant stated the flight supervisors expressed lack of concern for attendants' deteriorating health concerns.

Narrative

Shortly after take-off (below 10;000 ft.); the Purser initiated an all-call indicating that the Captain had received a message from ATC that sparks were seen shooting from the aircraft upon take-off and climb out. The Purser informed us that the Captain did not want us to begin our services and to await further instructions. Approximately 10 minutes later; we received another all-call from the Purser informing us that we would be returning to ZZZ Airport. This return flight would take approximately 45 minutes to one hour as we were too heavy with to land with the fuel amounts we had on board and would need to dump fuel. We were instructed to do a water service during this time. We were also told by the Purser that the Captain would make the initial announcement to the customers explaining the reason for our return to ZZZ. All necessary announcement (subsequent to the Captain announcement ) were made by the in-flight crew including what some passengers may or may not see (for example; the actually fuel dumping process; fire trucks upon landing; etc.). About 30 minutes into the flight; there was an electrical/burning odor detected in the lavatory near door XL and to a lesser extent in the lavatory near door XR. We were informed as well by the Purser that there were no special instructions and there would be no need for a cabin prep. We landed normally. The deplaning door was opened at XA:08. Concurrent with the door being opened; a pronounced toxic fume odor emanated throughout the entire cabin. Passengers deplaned however we did have XX wheelchair assistance customers. Due to our unexpected return and the late hour; the deplaning of those customers took from XA:08-XC:00. My concern (from a health standpoint) is that during these two hours; I started to experience an irritated; slight burning sensation in my eyes; a slight sore throat and a headache that even now as I write this a day later can still be discerned. I also experienced a slight nauseous feeling in my stomach. When in-flight Supervisors inquired as to how the crew was doing; I believe the exact question was 'are you all okay'? That question was asked when the door was first opened at XA:08. No one from Management made any further inquiries as to our state of well-being. I think that after two hours of remaining on the aircraft with the presence of the aforementioned fumes and odors that this is what led to the deterioration of my health and well-being.